1This is a terse description of the new features added to bash-5.1 since 2the release of bash-5.0. As always, the manual page (doc/bash.1) is 3the place to look for complete descriptions. 4 51. New Features in Bash 6 7a. `bind -x' now supports different bindings for different editing modes and 8 keymaps. 9 10b. Bash attempts to optimize the number of times it forks when executing 11 commands in subshells and from `bash -c'. 12 13c. Here documents and here strings now use pipes for the expanded document if 14 it's smaller than the pipe buffer size, reverting to temporary files if it's 15 larger. 16 17d. There are new loadable builtins: mktemp, accept, mkfifo, csv, cut/lcut 18 19e. In posix mode, `trap -p' now displays signals whose disposition is SIG_DFL 20 and those that were SIG_IGN when the shell starts. 21 22f. The shell now expands the history number (e.g., in PS1) even if it is not 23 currently saving commands to the history list. 24 25g. `read -e' may now be used with arbitrary file descriptors (`read -u N'). 26 27h. The `select' builtin now runs traps if its internal call to the read builtin 28 is interrupted by a signal. 29 30i. SRANDOM: a new variable that expands to a 32-bit random number that is not 31 produced by an LCRNG, and uses getrandom/getentropy, falling back to 32 /dev/urandom or arc4random if available. There is a fallback generator if 33 none of these are available. 34 35j. shell-transpose-words: a new bindable readline command that uses the same 36 definition of word as shell-forward-word, etc. 37 38k. The shell now adds default bindings for shell-forward-word, 39 shell-backward-word, shell-transpose-words, and shell-kill-word. 40 41l. Bash now allows ARGV0 appearing in the initial shell environment to set $0. 42 43m. If `unset' is executed without option arguments, bash tries to unset a shell 44 function if a name argument cannot be a shell variable name because it's not 45 an identifier. 46 47n. The `test -N' operator uses nanosecond timestamp granularity if it's 48 available. 49 50o. Bash posix mode now treats assignment statements preceding shell function 51 definitions the same as in its default mode, since POSIX has changed and 52 no longer requires those assignments to persist after the function returns 53 (POSIX interp 654). 54 55p. BASH_REMATCH is no longer readonly. 56 57q. wait: has a new -p VARNAME option, which stores the PID returned by `wait -n' 58 or `wait' without arguments. 59 60r. Sorting the results of pathname expansion now uses byte-by-byte comparisons 61 if two strings collate equally to impose a total order; the result of a 62 POSIX interpretation. 63 64s. Bash now allows SIGINT trap handlers to execute recursively. 65 66t. Bash now saves and restores state around setting and unsetting posix mode, 67 instead of having unsetting posix mode set a known state. 68 69u. Process substitution is now available in posix mode. 70 71v. READLINE_MARK: a new variable available while executing commands bound with 72 `bind -x', contains the value of the mark. 73 74w. Bash removes SIGCHLD from the set of blocked signals if it's blocked at shell 75 startup. 76 77x. `test -v N' can now test whether or not positional parameter N is set. 78 79y. `local' now honors the `-p' option to display all local variables at the 80 current context. 81 82z. The `@a' variable transformation now prints attributes for unset array 83 variables. 84 85aa. The `@A' variable transformation now prints a declare command that sets a 86 variable's attributes if the variable has attributes but is unset. 87 88bb. `declare' and `local' now have a -I option that inherits attributes and 89 value from a variable with the same name at a previous scope. 90 91cc. When run from a -c command, `jobs' now reports the status of completed jobs. 92 93dd. New `U', `u', and `L' parameter transformations to convert to uppercase, 94 convert first character to uppercase, and convert to lowercase, 95 respectively. 96 97ee. PROMPT_COMMAND: can now be an array variable, each element of which can 98 contain a command to be executed like a string PROMPT_COMMAND variable. 99 100ff. `ulimit' has a -R option to report and set the RLIMIT_RTTIME resource. 101 102gg. Associative arrays may be assigned using a list of key-value pairs within 103 a compound assignment. Compound assignments where the words are not of 104 the form [key]=value are assumed to be key-value assignments. A missing or 105 empty key is an error; a missing value is treated as NULL. Assignments may 106 not mix the two forms. 107 108hh. New `K' parameter transformation to display associative arrays as key- 109 value pairs. 110 111ii. Writing history to syslog now handles messages longer than the syslog max 112 length by writing multiple messages with a sequence number. 113 114jj. SECONDS and RANDOM may now be assigned using arithmetic expressions, since 115 they are nominally integer variables. LINENO is not an integer variable. 116 117kk. Bash temporarily suppresses the verbose option when running the DEBUG trap 118 while running a command from the `fc' builtin. 119 120ll. `wait -n' now accepts a list of job specifications as arguments and will 121 wait for the first one in the list to change state. 122 123mm. The associative array implementation can now dynamically increase the 124 size of the hash table based on insertion patterns. 125 126nn. HISTFILE is now readonly in a restricted shell. 127 128oo. The bash malloc now returns memory that is 16-byte aligned on 64-bit 129 systems. 130 131pp. If the hash builtin is listing hashed filenames portably, don't print 132 anything if the table is empty. 133 134qq. GLOBIGNORE now ignores `.' and `..' as a terminal pathname component. 135 136rr. Bash attempts to optimize away forks in the last command in a function body 137 under appropriate circumstances. 138 139ss. The globbing code now uses fnmatch(3) to check collation elements (if 140 available) even in cases without multibyte characters. 141 142tt. The `fg' and `bg' builtins now return an error in a command substitution 143 when asked to restart a job inherited from the parent shell. 144 145uu. The shell now attempts to unlink all FIFOs on exit, whether a consuming 146 process has finished with them or not. 147 148vv. There is a new contributed loadable builtin: asort. 149 1502. New Features in Readline 151 152a. If a second consecutive completion attempt produces matches where the first 153 did not, treat it as a new completion attempt and insert a match as 154 appropriate. 155 156b. Bracketed paste mode works in more places: incremental search strings, vi 157 overstrike mode, character search, and reading numeric arguments. 158 159c. Readline automatically switches to horizontal scrolling if the terminal has 160 only one line. 161 162d. Unbinding all key sequences bound to a particular readline function now 163 descends into keymaps for multi-key sequences. 164 165e. rl-clear-display: new bindable command that clears the screen and, if 166 possible, the scrollback buffer (bound to emacs mode M-C-l by default). 167 168f. New active mark and face feature: when enabled, it will highlight the text 169 inserted by a bracketed paste (the `active region') and the text found by 170 incremental and non-incremental history searches. This is tied to bracketed 171 paste and can be disabled by turning off bracketed paste. 172 173g. Readline sets the mark in several additional commands. 174 175h. Bracketed paste mode is enabled by default. 176 177i. Readline tries to take advantage of the more regular structure of UTF-8 178 characters to identify the beginning and end of characters when moving 179 through the line buffer. 180 181j. The bindable operate-and-get-next command (and its default bindings) are 182 now part of readline instead of a bash-specific addition. 183 184k. The signal cleanup code now blocks SIGINT while processing after a SIGINT. 185 186------------------------------------------------------------------------------- 187This is a terse description of the new features added to bash-5.0 since 188the release of bash-4.4. As always, the manual page (doc/bash.1) is 189the place to look for complete descriptions. 190 1911. New Features in Bash 192 193a. The `wait' builtin can now wait for the last process substitution created. 194 195b. There is an EPOCHSECONDS variable, which expands to the time in seconds 196 since the Unix epoch. 197 198c. There is an EPOCHREALTIME variable, which expands to the time in seconds 199 since the Unix epoch with microsecond granularity. 200 201d. New loadable builtins: rm, stat, fdflags. 202 203e. BASH_ARGV0: a new variable that expands to $0 and sets $0 on assignment. 204 205f. When supplied a numeric argument, the shell-expand-line bindable readline 206 command does not perform quote removal and suppresses command and process 207 substitution. 208 209g. `history -d' understands negative arguments: negative arguments offset from 210 the end of the history list. 211 212h. The `name' argument to the `coproc' reserved word now undergoes word 213 expansion, so unique coprocs can be created in loops. 214 215i. A nameref name resolution loop in a function now resolves to a variable by 216 that name in the global scope. 217 218j. The `wait' builtin now has a `-f' option, which signifies to wait until the 219 specified job or process terminates, instead of waiting until it changes 220 state. 221 222k. There is a define in config-top.h that allows the shell to use a static 223 value for $PATH, overriding whatever is in the environment at startup, for 224 use by the restricted shell. 225 226l. Process substitution does not inherit the `v' option, like command 227 substitution. 228 229m. If a non-interactive shell with job control enabled detects that a foreground 230 job died due to SIGINT, it acts as if it received the SIGINT. 231 232n. The SIGCHLD trap is run once for each exiting child process even if job 233 control is not enabled when the shell is in Posix mode. 234 235o. A new shopt option: localvar_inherit; if set, a local variable inherits the 236 value of a variable with the same name at the nearest preceding scope. 237 238p. `bind -r' now checks whether a key sequence is bound before binding it to 239 NULL, to avoid creating keymaps for a multi-key sequence. 240 241q. A numeric argument to the line editing `operate-and-get-next' command 242 specifies which history entry to use. 243 244r. The positional parameters are now assigned before running the shell startup 245 files, so startup files can use $@. 246 247s. There is a compile-time option that forces the shell to disable the check 248 for an inherited OLDPWD being a directory. 249 250t. The `history' builtin can now delete ranges of history entries using 251 `-d start-end'. 252 253u. The `vi-edit-and-execute-command' bindable readline command now puts readline 254 back in vi insertion mode after executing commands from the edited file. 255 256v. The command completion code now matches aliases and shell function names 257 case-insensitively if the readline completion-ignore-case variable is set. 258 259w. There is a new `assoc_expand_once' shell option that attempts to expand 260 associative array subscripts only once. 261 262x. The shell only sets up BASH_ARGV and BASH_ARGC at startup if extended 263 debugging mode is active. The old behavior of unconditionally setting them 264 is available as part of the shell compatibility options. 265 266y. The `umask' builtin now allows modes and masks greater than octal 777. 267 268z. The `times' builtin now honors the current locale when printing a decimal 269 point. 270 271aa. There is a new (disabled by default, undocumented) shell option to enable 272 and disable sending history to syslog at runtime. 273 274bb. Bash no longer allows variable assignments preceding a special builtin that 275 changes variable attributes to propagate back to the calling environment 276 unless the compatibility level is 44 or lower. 277 278cc. You can set the default value for $HISTSIZE at build time in config-top.h. 279 280dd. The `complete' builtin now accepts a -I option that applies the completion 281 to the initial word on the line. 282 283ee. The internal bash malloc now uses mmap (if available) to satisfy requests 284 greater than 128K bytes, so free can use mfree to return the pages to the 285 kernel. 286 287ff. The shell doesn't automatically set BASH_ARGC and BASH_ARGV at startup 288 unless it's in debugging mode, as the documentation has always said, but 289 will dynamically create them if a script references them at the top level 290 without having enabled debugging mode. 291 292gg. The localvar_inherit option will not attempt to inherit a value from a 293 variable of an incompatible type (indexed vs. associative arrays, for 294 example). 295 296hh. The `globasciiranges' option is now enabled by default; it can be set to 297 off by default at configuration time. 298 299ii. Associative and indexed arrays now allow subscripts consisting solely of 300 whitespace. 301 302jj. `checkwinsize' is now enabled by default. 303 304kk. The `localvar_unset' shopt option is now visible and documented. 305 306ll. The `progcomp_alias' shopt option is now visible and documented. 307 308mm. The signal name processing code now understands `SIGRTMIN+n' all the way 309 up to SIGRTMAX. 310 311nn. There is a new `seq' loadable builtin. 312 313oo. Trap execution now honors the (internal) max invocations of `eval', since 314 traps are supposed to be executed as if using `eval'. 315 316pp. The $_ variable doesn't change when the shell executes a command that forks. 317 318qq. The `kill' builtin now supports -sSIGNAME and -nSIGNUM, even though 319 conforming applications aren't supposed to use them. 320 321rr. POSIX mode now enables the `shift_verbose' option. 322 3232. New Features in Readline 324 325a. Non-incremental vi-mode search (`N', `n') can search for a shell pattern, as 326 Posix specifies (uses fnmatch(3) if available). 327 328b. There are new `next-screen-line' and `previous-screen-line' bindable 329 commands, which move the cursor to the same column in the next, or previous, 330 physical line, respectively. 331 332c. There are default key bindings for control-arrow-key key combinations. 333 334d. A negative argument (-N) to `quoted-insert' means to insert the next N 335 characters using quoted-insert. 336 337e. New public function: rl_check_signals(), which allows applications to 338 respond to signals that readline catches while waiting for input using 339 a custom read function. 340 341f. There is new support for conditionally testing the readline version in an 342 inputrc file, with a full set of arithmetic comparison operators available. 343 344g. There is a simple variable comparison facility available for use within an 345 inputrc file. Allowable operators are equality and inequality; string 346 variables may be compared to a value; boolean variables must be compared to 347 either `on' or `off'; variable names are separated from the operator by 348 whitespace. 349 350h. The history expansion library now understands command and process 351 substitution and extended globbing and allows them to appear anywhere in a 352 word. 353 354i. The history library has a new variable that allows applications to set the 355 initial quoting state, so quoting state can be inherited from a previous 356 line. 357 358j. Readline now allows application-defined keymap names; there is a new public 359 function, rl_set_keymap_name(), to do that. 360 361k. The "Insert" keypad key, if available, now puts readline into overwrite 362 mode. 363 364------------------------------------------------------------------------------- 365This is a terse description of the new features added to bash-4.4 since 366the release of bash-4.3. As always, the manual page (doc/bash.1) is 367the place to look for complete descriptions. 368 3691. New Features in Bash 370 371a. There is now a settable configuration #define that will cause the shell 372 to exit if the shell is running setuid without the -p option and setuid 373 to the real uid fails. 374 375b. Command and process substitutions now turn off the `-v' option when 376 executing, as other shells seem to do. 377 378c. The default value for the `checkhash' shell option may now be set at 379 compile time with a #define. 380 381d. The `mapfile' builtin now has a -d option to use an arbitrary character 382 as the record delimiter, and a -t option to strip the delimiter as 383 supplied with -d. 384 385e. The maximum number of nested recursive calls to `eval' is now settable in 386 config-top.h; the default is no limit. 387 388f. The `-p' option to declare and similar builtins will display attributes for 389 named variables even when those variables have not been assigned values 390 (which are technically unset). 391 392g. The maximum number of nested recursive calls to `source' is now settable 393 in config-top.h; the default is no limit. 394 395h. All builtin commands recognize the `--help' option and print a usage 396 summary. 397 398i. Bash does not allow function names containing `/' and `=' to be exported. 399 400j. The `ulimit' builtin has new -k (kqueues) and -P (pseudoterminals) options. 401 402k. The shell now allows `time ; othercommand' to time null commands. 403 404l. There is a new `--enable-function-import' configuration option to allow 405 importing shell functions from the environment; import is enabled by 406 default. 407 408m. `printf -v var ""' will now set `var' to the empty string, as if `var=""' 409 had been executed. 410 411n. GLOBIGNORE, the pattern substitution word expansion, and programmable 412 completion match filtering now honor the value of the `nocasematch' option. 413 414o. There is a new ${parameter@spec} family of operators to transform the 415 value of `parameter'. 416 417p. Bash no longer attempts to perform compound assignment if a variable on the 418 rhs of an assignment statement argument to `declare' has the form of a 419 compound assignment (e.g., w='(word)' ; declare foo=$w); compound 420 assignments are accepted if the variable was already declared as an array, 421 but with a warning. 422 423q. The declare builtin no longer displays array variables using the compound 424 assignment syntax with quotes; that will generate warnings when re-used as 425 input, and isn't necessary. 426 427r. Executing the rhs of && and || will no longer cause the shell to fork if 428 it's not necessary. 429 430s. The `local' builtin takes a new argument: `-', which will cause it to save 431 and the single-letter shell options and restore their previous values at 432 function return. 433 434t. `complete' and `compgen' have a new `-o nosort' option, which forces 435 readline to not sort the completion matches. 436 437u. Bash now allows waiting for the most recent process substitution, since it 438 appears as $!. 439 440v. The `unset' builtin now unsets a scalar variable if it is subscripted with 441 a `0', analogous to the ${var[0]} expansion. 442 443w. `set -i' is no longer valid, as in other shells. 444 445x. BASH_SUBSHELL is now updated for process substitution and group commands 446 in pipelines, and is available with the same value when running any exit 447 trap. 448 449y. Bash now checks $INSIDE_EMACS as well as $EMACS when deciding whether or 450 not bash is being run in a GNU Emacs shell window. 451 452z. Bash now treats SIGINT received when running a non-builtin command in a 453 loop the way it has traditionally treated running a builtin command: 454 running any trap handler and breaking out of the loop. 455 456aa. New variable: EXECIGNORE; a colon-separate list of patterns that will 457 cause matching filenames to be ignored when searching for commands. 458 459bb. Aliases whose value ends in a shell metacharacter now expand in a way to 460 allow them to be `pasted' to the next token, which can potentially change 461 the meaning of a command (e.g., turning `&' into `&&'). 462 463cc. `make install' now installs the example loadable builtins and a set of 464 bash headers to use when developing new loadable builtins. 465 466dd. `enable -f' now attempts to call functions named BUILTIN_builtin_load when 467 loading BUILTIN, and BUILTIN_builtin_unload when deleting it. This allows 468 loadable builtins to run initialization and cleanup code. 469 470ee. There is a new BASH_LOADABLES_PATH variable containing a list of directories 471 where the `enable -f' command looks for shared objects containing loadable 472 builtins. 473 474ff. The `complete_fullquote' option to `shopt' changes filename completion to 475 quote all shell metacharacters in filenames and directory names. 476 477gg. The `kill' builtin now has a `-L' option, equivalent to `-l', for 478 compatibility with Linux standalone versions of kill. 479 480hh. BASH_COMPAT and FUNCNEST can be inherited and set from the shell's initial 481 environment. 482 483ii. inherit_errexit: a new `shopt' option that, when set, causes command 484 substitutions to inherit the -e option. By default, those subshells disable 485 -e. It's enabled as part of turning on posix mode. 486 487jj. New prompt string: PS0. Expanded and displayed by interactive shells after 488 reading a complete command but before executing it. 489 490kk. Interactive shells now behave as if SIGTSTP/SIGTTIN/SIGTTOU are set to 491 SIG_DFL when the shell is started, so they are set to SIG_DFL in child 492 processes. 493 494ll. Posix-mode shells now allow double quotes to quote the history expansion 495 character. 496 497mm. OLDPWD can be inherited from the environment if it names a directory. 498 499nn. Shells running as root no longer inherit PS4 from the environment, closing 500 a security hole involving PS4 expansion performing command substitution. 501 502oo. If executing an implicit `cd' when the `autocd' option is set, bash will 503 now invoke a function named `cd' if one exists before executing the `cd' 504 builtin. 505 506pp. Value conversions (arithmetic expansions, case modification, etc.) now 507 happen when assigning elements of an array using compound assignment. 508 509qq. There is a new option settable in config-top.h that makes multiple 510 directory arguments to `cd' a fatal error. 511 512rr. Bash now uses mktemp() when creating internal temporary files; it produces 513 a warning at build time on many Linux systems. 514 5152. New Features in Readline 516 517a. The history truncation code now uses the same error recovery mechanism as 518 the history writing code, and restores the old version of the history file 519 on error. The error recovery mechanism handles symlinked history files. 520 521b. There is a new bindable variable, `enable-bracketed-paste', which enables 522 support for a terminal's bracketed paste mode. 523 524c. The editing mode indicators can now be strings and are user-settable 525 (new `emacs-mode-string', `vi-cmd-mode-string' and `vi-ins-mode-string' 526 variables). Mode strings can contain invisible character sequences. 527 Setting mode strings to null strings restores the defaults. 528 529d. Prompt expansion adds the mode string to the last line of a multi-line 530 prompt (one with embedded newlines). 531 532e. There is a new bindable variable, `colored-completion-prefix', which, if 533 set, causes the common prefix of a set of possible completions to be 534 displayed in color. 535 536f. There is a new bindable command `vi-yank-pop', a vi-mode version of emacs- 537 mode yank-pop. 538 539g. The redisplay code underwent several efficiency improvements for multibyte 540 locales. 541 542h. The insert-char function attempts to batch-insert all pending typeahead 543 that maps to self-insert, as long as it is coming from the terminal. 544 545i. rl_callback_sigcleanup: a new application function that can clean up and 546 unset any state set by readline's callback mode. Intended to be used 547 after a signal. 548 549j. If an incremental search string has its last character removed with DEL, the 550 resulting empty search string no longer matches the previous line. 551 552k. If readline reads a history file that begins with `#' (or the value of 553 the history comment character) and has enabled history timestamps, the 554 history entries are assumed to be delimited by timestamps. This allows 555 multi-line history entries. 556 557l. Readline now throws an error if it parses a key binding without a 558 terminating `:' or whitespace. 559 560m. The default binding for ^W in vi mode now uses word boundaries specified 561 by Posix (vi-unix-word-rubout is bindable command name). 562 563n. rl_clear_visible_line: new application-callable function; clears all 564 screen lines occupied by the current visible readline line. 565 566o. rl_tty_set_echoing: application-callable function that controls whether 567 or not readline thinks it is echoing terminal output. 568 569p. Handle >| and strings of digits preceding and following redirection 570 specifications as single tokens when tokenizing the line for history 571 expansion. 572 573q. Fixed a bug with displaying completions when the prefix display length 574 is greater than the length of the completions to be displayed. 575 576r. The :p history modifier now applies to the entire line, so any expansion 577 specifying :p causes the line to be printed instead of expanded. 578 579s. New application-callable function: rl_pending_signal(): returns the signal 580 number of any signal readline has caught but not yet handled. 581 582t. New application-settable variable: rl_persistent_signal_handlers: if set 583 to a non-zero value, readline will enable the readline-6.2 signal handler 584 behavior in callback mode: handlers are installed when 585 rl_callback_handler_install is called and removed removed when a complete 586 line has been read. 587 588------------------------------------------------------------------------------- 589This is a terse description of the new features added to bash-4.3 since 590the release of bash-4.2. As always, the manual page (doc/bash.1) is 591the place to look for complete descriptions. 592 5931. New Features in Bash 594 595a. The `helptopic' completion action now maps to all the help topics, not just 596 the shell builtins. 597 598b. The `help' builtin no longer does prefix substring matching first, so 599 `help read' does not match `readonly', but will do it if exact string 600 matching fails. 601 602c. The shell can be compiled to not display a message about processes that 603 terminate due to SIGTERM. 604 605d. Non-interactive shells now react to the setting of checkwinsize and set 606 LINES and COLUMNS after a foreground job exits. 607 608e. There is a new shell option, `globasciiranges', which, when set to on, 609 forces globbing range comparisons to use character ordering as if they 610 were run in the C locale. 611 612f. There is a new shell option, `direxpand', which makes filename completion 613 expand variables in directory names in the way bash-4.1 did. 614 615g. In Posix mode, the `command' builtin does not change whether or not a 616 builtin it shadows is treated as an assignment builtin. 617 618h. The `return' and `exit' builtins accept negative exit status arguments. 619 620i. The word completion code checks whether or not a filename containing a 621 shell variable expands to a directory name and appends `/' to the word 622 as appropriate. The same code expands shell variables in command names 623 when performing command completion. 624 625j. In Posix mode, it is now an error to attempt to define a shell function 626 with the same name as a Posix special builtin. 627 628k. When compiled for strict Posix conformance, history expansion is disabled 629 by default. 630 631l. The history expansion character (!) does not cause history expansion when 632 followed by the closing quote in a double-quoted string. 633 634m. `complete' and its siblings compgen/compopt now takes a new `-o noquote' 635 option to inhibit quoting of the completions. 636 637n. Setting HISTSIZE to a value less than zero causes the history list to be 638 unlimited (setting it 0 zero disables the history list). 639 640o. Setting HISTFILESIZE to a value less than zero causes the history file size 641 to be unlimited (setting it to 0 causes the history file to be truncated 642 to zero size). 643 644p. The `read' builtin now skips NUL bytes in the input. 645 646q. There is a new `bind -X' option to print all key sequences bound to Unix 647 commands. 648 649r. When in Posix mode, `read' is interruptible by a trapped signal. After 650 running the trap handler, read returns 128+signal and throws away any 651 partially-read input. 652 653s. The command completion code skips whitespace and assignment statements 654 before looking for the command name word to be completed. 655 656t. The build process has a new mechanism for constructing separate help files 657 that better reflects the current set of compilation options. 658 659u. The -nt and -ot options to test now work with files with nanosecond 660 timestamp resolution. 661 662v. The shell saves the command history in any shell for which history is 663 enabled and HISTFILE is set, not just interactive shells. 664 665w. The shell has `nameref' variables and new -n(/+n) options to declare and 666 unset to use them, and a `test -R' option to test for them. 667 668x. The shell now allows assigning, referencing, and unsetting elements of 669 indexed arrays using negative subscripts (a[-1]=2, echo ${a[-1]}) which 670 count back from the last element of the array. 671 672y. The {x}<word redirection feature now allows words like {array[ind]} and 673 can use variables with special meanings to the shell (e.g., BASH_XTRACEFD). 674 675z. There is a new CHILD_MAX special shell variable; its value controls the 676 number of exited child statues the shell remembers. 677 678aa. There is a new configuration option (--enable-direxpand-default) that 679 causes the `direxpand' shell option to be enabled by default. 680 681bb. Bash does not do anything special to ensure that the file descriptor 682 assigned to X in {x}<foo remains open after the block containing it 683 completes. 684 685cc. The `wait' builtin has a new `-n' option to wait for the next child to 686 change status. 687 688dd. The `printf' %(...)T format specifier now uses the current time if no 689 argument is supplied. 690 691ee. There is a new variable, BASH_COMPAT, that controls the current shell 692 compatibility level. 693 694ff. The `popd' builtin now treats additional arguments as errors. 695 696gg. The brace expansion code now treats a failed sequence expansion as a 697 simple string and will continue to expand brace terms in the remainder 698 of the word. 699 700hh. Shells started to run process substitutions now run any trap set on EXIT. 701 702ii. The fc builtin now interprets -0 as the current command line. 703 704jj. Completing directory names containing shell variables now adds a trailing 705 slash if the expanded result is a directory. 706 707kk. `cd' has a new `-@' option to browse a file's extended attributes on 708 systems that support O_XATTR. 709 710ll. The test/[/[[ `-v variable' binary operator now understands array 711 references. 712 7132. New Features in Readline 714 715a. Readline is now more responsive to SIGHUP and other fatal signals when 716 reading input from the terminal or performing word completion but no 717 longer attempts to run any not-allowable functions from a signal handler 718 context. 719 720b. There are new bindable commands to search the history for the string of 721 characters between the beginning of the line and the point 722 (history-substring-search-forward, history-substring-search-backward) 723 724c. Readline allows quoted strings as the values of variables when setting 725 them with `set'. As a side effect, trailing spaces and tabs are ignored 726 when setting a string variable's value. 727 728d. The history library creates a backup of the history file when writing it 729 and restores the backup on a write error. 730 731e. New application-settable variable: rl_filename_stat_hook: a function called 732 with a filename before using it in a call to stat(2). Bash uses it to 733 expand shell variables so things like $HOME/Downloads have a slash 734 appended. 735 736f. New bindable function `print-last-kbd-macro', prints the most-recently- 737 defined keyboard macro in a reusable format. 738 739g. New user-settable variable `colored-stats', enables use of colored text 740 to denote file types when displaying possible completions (colored analog 741 of visible-stats). 742 743h. New user-settable variable `keyseq-timout', acts as an inter-character 744 timeout when reading input or incremental search strings. 745 746i. New application-callable function: rl_clear_history. Clears the history list 747 and frees all readline-associated private data. 748 749j. New user-settable variable, show-mode-in-prompt, adds a characters to the 750 beginning of the prompt indicating the current editing mode. 751 752k. New application-settable variable: rl_input_available_hook; function to be 753 called when readline detects there is data available on its input file 754 descriptor. 755 756l. Readline calls an application-set event hook (rl_event_hook) after it gets 757 a signal while reading input (read returns -1/EINTR but readline does not 758 handle the signal immediately) to allow the application to handle or 759 otherwise note it. 760 761m. If the user-settable variable `history-size' is set to a value less than 762 0, the history list size is unlimited. 763 764n. New application-settable variable: rl_signal_event_hook; function that is 765 called when readline is reading terminal input and read(2) is interrupted 766 by a signal. Currently not called for SIGHUP or SIGTERM. 767 768o. rl_change_environment: new application-settable variable that controls 769 whether or not Readline modifies the environment (currently readline 770 modifies only LINES and COLUMNS). 771 772------------------------------------------------------------------------------- 773This is a terse description of the new features added to bash-4.2 since 774the release of bash-4.1. As always, the manual page (doc/bash.1) is 775the place to look for complete descriptions. 776 7771. New Features in Bash 778 779a. `exec -a foo' now sets $0 to `foo' in an executable shell script without a 780 leading #!. 781 782b. Subshells begun to execute command substitutions or run shell functions or 783 builtins in subshells do not reset trap strings until a new trap is 784 specified. This allows $(trap) to display the caller's traps and the 785 trap strings to persist until a new trap is set. 786 787c. `trap -p' will now show signals ignored at shell startup, though their 788 disposition still cannot be modified. 789 790d. $'...', echo, and printf understand \uXXXX and \UXXXXXXXX escape sequences. 791 792e. declare/typeset has a new `-g' option, which creates variables in the 793 global scope even when run in a shell function. 794 795f. test/[/[[ have a new -v variable unary operator, which returns success if 796 `variable' has been set. 797 798g. Posix parsing changes to allow `! time command' and multiple consecutive 799 instances of `!' (which toggle) and `time' (which have no cumulative 800 effect). 801 802h. Posix change to allow `time' as a command by itself to print the elapsed 803 user, system, and real times for the shell and its children. 804 805j. $((...)) is always parsed as an arithmetic expansion first, instead of as 806 a potential nested command substitution, as Posix requires. 807 808k. A new FUNCNEST variable to allow the user to control the maximum shell 809 function nesting (recursive execution) level. 810 811l. The mapfile builtin now supplies a third argument to the callback command: 812 the line about to be assigned to the supplied array index. 813 814m. The printf builtin has a new %(fmt)T specifier, which allows time values 815 to use strftime-like formatting. 816 817n. There is a new `compat41' shell option. 818 819o. The cd builtin has a new Posix-mandated `-e' option. 820 821p. Negative subscripts to indexed arrays, previously errors, now are treated 822 as offsets from the maximum assigned index + 1. 823 824q. Negative length specifications in the ${var:offset:length} expansion, 825 previously errors, are now treated as offsets from the end of the variable. 826 827r. Parsing change to allow `time -p --'. 828 829s. Posix-mode parsing change to not recognize `time' as a keyword if the 830 following token begins with a `-'. This means no more Posix-mode 831 `time -p'. Posix interpretation 267. 832 833t. There is a new `lastpipe' shell option that runs the last command of a 834 pipeline in the current shell context. The lastpipe option has no 835 effect if job control is enabled. 836 837u. History expansion no longer expands the `$!' variable expansion. 838 839v. Posix mode shells no longer exit if a variable assignment error occurs 840 with an assignment preceding a command that is not a special builtin. 841 842w. Non-interactive mode shells exit if -u is enabled and an attempt is made 843 to use an unset variable with the % or # expansions, the `//', `^', or 844 `,' expansions, or the parameter length expansion. 845 846x. Posix-mode shells use the argument passed to `.' as-is if a $PATH search 847 fails, effectively searching the current directory. Posix-2008 change. 848 8492. New Features in Readline 850 851a. The history library does not try to write the history filename in the 852 current directory if $HOME is unset. This closes a potential security 853 problem if the application does not specify a history filename. 854 855b. New bindable variable `completion-display-width' to set the number of 856 columns used when displaying completions. 857 858c. New bindable variable `completion-case-map' to cause case-insensitive 859 completion to treat `-' and `_' as identical. 860 861d. There are new bindable vi-mode command names to avoid readline's case- 862 insensitive matching not allowing them to be bound separately. 863 864e. New bindable variable `menu-complete-display-prefix' causes the menu 865 completion code to display the common prefix of the possible completions 866 before cycling through the list, instead of after. 867 868------------------------------------------------------------------------------- 869This is a terse description of the new features added to bash-4.1 since 870the release of bash-4.0. As always, the manual page (doc/bash.1) is 871the place to look for complete descriptions. 872 8731. New Features in Bash 874 875a. Here-documents within $(...) command substitutions may once more be 876 delimited by the closing right paren, instead of requiring a newline. 877 878b. Bash's file status checks (executable, readable, etc.) now take file 879 system ACLs into account on file systems that support them. 880 881c. Bash now passes environment variables with names that are not valid 882 shell variable names through into the environment passed to child 883 processes. 884 885d. The `execute-unix-command' readline function now attempts to clear and 886 reuse the current line rather than move to a new one after the command 887 executes. 888 889e. `printf -v' can now assign values to array indices. 890 891f. New `complete -E' and `compopt -E' options that work on the "empty" 892 completion: completion attempted on an empty command line. 893 894g. New complete/compgen/compopt -D option to define a `default' completion: 895 a completion to be invoked on command for which no completion has been 896 defined. If this function returns 124, programmable completion is 897 attempted again, allowing a user to dynamically build a set of completions 898 as completion is attempted by having the default completion function 899 install individual completion functions each time it is invoked. 900 901h. When displaying associative arrays, subscripts are now quoted. 902 903i. Changes to dabbrev-expand to make it more `emacs-like': no space appended 904 after matches, completions are not sorted, and most recent history entries 905 are presented first. 906 907j. The [[ and (( commands are now subject to the setting of `set -e' and the 908 ERR trap. 909 910k. The source/. builtin now removes NUL bytes from the file before attempting 911 to parse commands. 912 913l. There is a new configuration option (in config-top.h) that forces bash to 914 forward all history entries to syslog. 915 916m. A new variable $BASHOPTS to export shell options settable using `shopt' to 917 child processes. 918 919n. There is a new confgure option that forces the extglob option to be 920 enabled by default. 921 922o. New variable $BASH_XTRACEFD; when set to an integer bash will write xtrace 923 output to that file descriptor. 924 925p. If the optional left-hand-side of a redirection is of the form {var}, the 926 shell assigns the file descriptor used to $var or uses $var as the file 927 descriptor to move or close, depending on the redirection operator. 928 929q. The < and > operators to the [[ conditional command now do string 930 comparison according to the current locale if the compatibility level 931 is greater than 40. 932 933r. Programmable completion now uses the completion for `b' instead of `a' 934 when completion is attempted on a line like: a $(b c. 935 936s. Force extglob on temporarily when parsing the pattern argument to 937 the == and != operators to the [[ command, for compatibility. 938 939t. Changed the behavior of interrupting the wait builtin when a SIGCHLD is 940 received and a trap on SIGCHLD is set to be Posix-mode only. 941 942u. The read builtin has a new `-N nchars' option, which reads exactly NCHARS 943 characters, ignoring delimiters like newline. 944 945v. The mapfile/readarray builtin no longer stores the commands it invokes via 946 callbacks in the history list. 947 948w. There is a new `compat40' shopt option. 949 9502. New Features in Readline 951 952a. New bindable function: menu-complete-backward. 953 954b. In the vi insertion keymap, C-n is now bound to menu-complete by default, 955 and C-p to menu-complete-backward. 956 957c. When in vi command mode, repeatedly hitting ESC now does nothing, even 958 when ESC introduces a bound key sequence. This is closer to how 959 historical vi behaves. 960 961d. New bindable function: skip-csi-sequence. Can be used as a default to 962 consume key sequences generated by keys like Home and End without having 963 to bind all keys. 964 965e. New application-settable function: rl_filename_rewrite_hook. Can be used 966 to rewite or modify filenames read from the file system before they are 967 compared to the word to be completed. 968 969f. New bindable variable: skip-completed-text, active when completing in the 970 middle of a word. If enabled, it means that characters in the completion 971 that match characters in the remainder of the word are "skipped" rather 972 than inserted into the line. 973 974g. The pre-readline-6.0 version of menu completion is available as 975 "old-menu-complete" for users who do not like the readline-6.0 version. 976 977h. New bindable variable: echo-control-characters. If enabled, and the 978 tty ECHOCTL bit is set, controls the echoing of characters corresponding 979 to keyboard-generated signals. 980 981i. New bindable variable: enable-meta-key. Controls whether or not readline 982 sends the smm/rmm sequences if the terminal indicates it has a meta key 983 that enables eight-bit characters. 984 985------------------------------------------------------------------------------- 986This is a terse description of the new features added to bash-4.0 since 987the release of bash-3.2. As always, the manual page (doc/bash.1) is 988the place to look for complete descriptions. 989 9901. New Features in Bash 991 992a. When using substring expansion on the positional parameters, a starting 993 index of 0 now causes $0 to be prefixed to the list. 994 995b. The `help' builtin now prints its columns with entries sorted vertically 996 rather than horizontally. 997 998c. There is a new variable, $BASHPID, which always returns the process id of 999 the current shell. 1000 1001d. There is a new `autocd' option that, when enabled, causes bash to attempt 1002 to `cd' to a directory name that is supplied as the first word of a 1003 simple command. 1004 1005e. There is a new `checkjobs' option that causes the shell to check for and 1006 report any running or stopped jobs at exit. 1007 1008f. The programmable completion code exports a new COMP_TYPE variable, set to 1009 a character describing the type of completion being attempted. 1010 1011g. The programmable completion code exports a new COMP_KEY variable, set to 1012 the character that caused the completion to be invoked (e.g., TAB). 1013 1014h. If creation of a child process fails due to insufficient resources, bash 1015 will try again several times before reporting failure. 1016 1017i. The programmable completion code now uses the same set of characters as 1018 readline when breaking the command line into a list of words. 1019 1020j. The block multiplier for the ulimit -c and -f options is now 512 when in 1021 Posix mode, as Posix specifies. 1022 1023k. Changed the behavior of the read builtin to save any partial input received 1024 in the specified variable when the read builtin times out. This also 1025 results in variables specified as arguments to read to be set to the empty 1026 string when there is no input available. When the read builtin times out, 1027 it returns an exit status greater than 128. 1028 1029l. The shell now has the notion of a `compatibility level', controlled by 1030 new variables settable by `shopt'. Setting this variable currently 1031 restores the bash-3.1 behavior when processing quoted strings on the rhs 1032 of the `=~' operator to the `[[' command. 1033 1034m. The `ulimit' builtin now has new -b (socket buffer size) and -T (number 1035 of threads) options. 1036 1037n. The -p option to `declare' now displays all variable values and attributes 1038 (or function values and attributes if used with -f). 1039 1040o. There is a new `compopt' builtin that allows completion functions to modify 1041 completion options for existing completions or the completion currently 1042 being executed. 1043 1044p. The `read' builtin has a new -i option which inserts text into the reply 1045 buffer when using readline. 1046 1047q. A new `-E' option to the complete builtin allows control of the default 1048 behavior for completion on an empty line. 1049 1050r. There is now limited support for completing command name words containing 1051 globbing characters. 1052 1053s. Changed format of internal help documentation for all builtins to roughly 1054 follow man page format. 1055 1056t. The `help' builtin now has a new -d option, to display a short description, 1057 and a -m option, to print help information in a man page-like format. 1058 1059u. There is a new `mapfile' builtin to populate an array with lines from a 1060 given file. The name `readarray' is a synonym. 1061 1062v. If a command is not found, the shell attempts to execute a shell function 1063 named `command_not_found_handle', supplying the command words as the 1064 function arguments. 1065 1066w. There is a new shell option: `globstar'. When enabled, the globbing code 1067 treats `**' specially -- it matches all directories (and files within 1068 them, when appropriate) recursively. 1069 1070x. There is a new shell option: `dirspell'. When enabled, the filename 1071 completion code performs spelling correction on directory names during 1072 completion. 1073 1074y. The `-t' option to the `read' builtin now supports fractional timeout 1075 values. 1076 1077z. Brace expansion now allows zero-padding of expanded numeric values and 1078 will add the proper number of zeroes to make sure all values contain the 1079 same number of digits. 1080 1081aa. There is a new bash-specific bindable readline function: `dabbrev-expand'. 1082 It uses menu completion on a set of words taken from the history list. 1083 1084bb. The command assigned to a key sequence with `bind -x' now sets two new 1085 variables in the environment of the executed command: READLINE_LINE_BUFFER 1086 and READLINE_POINT. The command can change the current readline line 1087 and cursor position by modifying READLINE_LINE_BUFFER and READLINE_POINT, 1088 respectively. 1089 1090cc. There is a new &>> redirection operator, which appends the standard output 1091 and standard error to the named file. 1092 1093dd. The parser now understands `|&' as a synonym for `2>&1 |', which redirects 1094 the standard error for a command through a pipe. 1095 1096ee. The new `;&' case statement action list terminator causes execution to 1097 continue with the action associated with the next pattern in the 1098 statement rather than terminating the command. 1099 1100ff. The new `;;&' case statement action list terminator causes the shell to 1101 test the next set of patterns after completing execution of the current 1102 action, rather than terminating the command. 1103 1104gg. The shell understands a new variable: PROMPT_DIRTRIM. When set to an 1105 integer value greater than zero, prompt expansion of \w and \W will 1106 retain only that number of trailing pathname components and replace 1107 the intervening characters with `...'. 1108 1109hh. There are new case-modifying word expansions: uppercase (^[^]) and 1110 lowercase (,[,]). They can work on either the first character or 1111 array element, or globally. They accept an optional shell pattern 1112 that determines which characters to modify. There is an optionally- 1113 configured feature to include capitalization operators. 1114 1115ii. The shell provides associative array variables, with the appropriate 1116 support to create, delete, assign values to, and expand them. 1117 1118jj. The `declare' builtin now has new -l (convert value to lowercase upon 1119 assignment) and -u (convert value to uppercase upon assignment) options. 1120 There is an optionally-configurable -c option to capitalize a value at 1121 assignment. 1122 1123kk. There is a new `coproc' reserved word that specifies a coprocess: an 1124 asynchronous command run with two pipes connected to the creating shell. 1125 Coprocs can be named. The input and output file descriptors and the 1126 PID of the coprocess are available to the calling shell in variables 1127 with coproc-specific names. 1128 1129ll. A value of 0 for the -t option to `read' now returns success if there is 1130 input available to be read from the specified file descriptor. 1131 1132mm. CDPATH and GLOBIGNORE are ignored when the shell is running in privileged 1133 mode. 1134 1135nn. New bindable readline functions shell-forward-word and shell-backward-word, 1136 which move forward and backward words delimited by shell metacharacters 1137 and honor shell quoting. 1138 1139oo. New bindable readline functions shell-backward-kill-word and shell-kill-word 1140 which kill words backward and forward, but use the same word boundaries 1141 as shell-forward-word and shell-backward-word. 1142 11432. New Features in Readline 1144 1145a. A new variable, rl_sort_completion_matches; allows applications to inhibit 1146 match list sorting (but beware: some things don't work right if 1147 applications do this). 1148 1149b. A new variable, rl_completion_invoking_key; allows applications to discover 1150 the key that invoked rl_complete or rl_menu_complete. 1151 1152c. The functions rl_block_sigint and rl_release_sigint are now public and 1153 available to calling applications who want to protect critical sections 1154 (like redisplay). 1155 1156d. The functions rl_save_state and rl_restore_state are now public and 1157 available to calling applications; documented rest of readline's state 1158 flag values. 1159 1160e. A new user-settable variable, `history-size', allows setting the maximum 1161 number of entries in the history list. 1162 1163f. There is a new implementation of menu completion, with several improvements 1164 over the old; the most notable improvement is a better `completions 1165 browsing' mode. 1166 1167g. The menu completion code now uses the rl_menu_completion_entry_function 1168 variable, allowing applications to provide their own menu completion 1169 generators. 1170 1171h. There is support for replacing a prefix of a pathname with a `...' when 1172 displaying possible completions. This is controllable by setting the 1173 `completion-prefix-display-length' variable. Matches with a common prefix 1174 longer than this value have the common prefix replaced with `...'. 1175 1176i. There is a new `revert-all-at-newline' variable. If enabled, readline will 1177 undo all outstanding changes to all history lines when `accept-line' is 1178 executed. 1179 1180j. If the kernel supports it, readline displays special characters 1181 corresponding to a keyboard-generated signal when the signal is received. 1182 1183------------------------------------------------------------------------------- 1184This is a terse description of the new features added to bash-3.2 since 1185the release of bash-3.1. As always, the manual page (doc/bash.1) is 1186the place to look for complete descriptions. 1187 11881. New Features in Bash 1189 1190a. Changed the parameter pattern replacement functions to not anchor the 1191 pattern at the beginning of the string if doing global replacement - that 1192 combination doesn't make any sense. 1193 1194b. When running in `word expansion only' mode (--wordexp option), inhibit 1195 process substitution. 1196 1197c. Loadable builtins now work on MacOS X 10.[34]. 1198 1199d. Shells running in posix mode no longer set $HOME, as POSIX requires. 1200 1201e. The code that checks for binary files being executed as shell scripts now 1202 checks only for NUL rather than any non-printing character. 1203 1204f. Quoting the string argument to the [[ command's =~ operator now forces 1205 string matching, as with the other pattern-matching operators. 1206 12072. New Features in Readline 1208 1209a. Calling applications can now set the keyboard timeout to 0, allowing 1210 poll-like behavior. 1211 1212b. The value of SYS_INPUTRC (configurable at compilation time) is now used as 1213 the default last-ditch startup file. 1214 1215c. The history file reading functions now allow windows-like \r\n line 1216 terminators. 1217 1218------------------------------------------------------------------------------- 1219This is a terse description of the new features added to bash-3.1 since 1220the release of bash-3.0. As always, the manual page (doc/bash.1) is 1221the place to look for complete descriptions. 1222 12231. New Features in Bash 1224 1225a. Bash now understands LC_TIME as a special variable so that time display 1226 tracks the current locale. 1227 1228b. BASH_ARGC, BASH_ARGV, BASH_SOURCE, and BASH_LINENO are no longer created 1229 as `invisible' variables and may not be unset. 1230 1231c. In POSIX mode, if `xpg_echo' option is enabled, the `echo' builtin doesn't 1232 try to interpret any options at all, as POSIX requires. 1233 1234d. The `bg' builtin now accepts multiple arguments, as POSIX seems to specify. 1235 1236e. Fixed vi-mode word completion and glob expansion to perform tilde 1237 expansion. 1238 1239f. The `**' mathematic exponentiation operator is now right-associative. 1240 1241g. The `ulimit' builtin has new options: -i (max number of pending signals), 1242 -q (max size of POSIX message queues), and -x (max number of file locks). 1243 1244h. A bare `%' once again expands to the current job when used as a job 1245 specifier. 1246 1247i. The `+=' assignment operator (append to the value of a string or array) is 1248 now supported for assignment statements and arguments to builtin commands 1249 that accept assignment statements. 1250 1251j. BASH_COMMAND now preserves its value when a DEBUG trap is executed. 1252 1253k. The `gnu_errfmt' option is enabled automatically if the shell is running 1254 in an emacs terminal window. 1255 1256l. New configuration option: --single-help-strings. Causes long help text 1257 to be written as a single string; intended to ease translation. 1258 1259m. The COMP_WORDBREAKS variable now causes the list of word break characters 1260 to be emptied when the variable is unset. 1261 1262n. An unquoted expansion of $* when $IFS is empty now causes the positional 1263 parameters to be concatenated if the expansion doesn't undergo word 1264 splitting. 1265 1266o. Bash now inherits $_ from the environment if it appears there at startup. 1267 1268p. New shell option: nocasematch. If non-zero, shell pattern matching ignores 1269 case when used by `case' and `[[' commands. 1270 1271q. The `printf' builtin takes a new option: -v var. That causes the output 1272 to be placed into var instead of on stdout. 1273 1274r. By default, the shell no longer reports processes dying from SIGPIPE. 1275 1276s. Bash now sets the extern variable `environ' to the export environment it 1277 creates, so C library functions that call getenv() (and can't use the 1278 shell-provided replacement) get current values of environment variables. 1279 1280t. A new configuration option, `--enable-strict-posix-default', which will 1281 build bash to be POSIX conforming by default. 1282 1283u. If compiled for strict POSIX conformance, LINES and COLUMNS may now 1284 override the true terminal size. 1285 12862. New Features in Readline 1287 1288a. The key sequence sent by the keypad `delete' key is now automatically 1289 bound to delete-char. 1290 1291b. A negative argument to menu-complete now cycles backward through the 1292 completion list. 1293 1294c. A new bindable readline variable: bind-tty-special-chars. If non-zero, 1295 readline will bind the terminal special characters to their readline 1296 equivalents when it's called (on by default). 1297 1298d. New bindable command: vi-rubout. Saves deleted text for possible 1299 reinsertion, as with any vi-mode `text modification' command; `X' is bound 1300 to this in vi command mode. 1301 1302e. A new external application-controllable variable that allows the LINES 1303 and COLUMNS environment variables to set the window size regardless of 1304 what the kernel returns: rl_prefer_env_winsize 1305 1306------------------------------------------------------------------------------- 1307This is a terse description of the new features added to bash-3.0 since 1308the release of bash-2.05b. As always, the manual page (doc/bash.1) is 1309the place to look for complete descriptions. 1310 13111. New Features in Bash 1312 1313a. ANSI string expansion now implements the \x{hexdigits} escape. 1314 1315b. There is a new loadable `strftime' builtin. 1316 1317c. New variable, COMP_WORDBREAKS, which controls the readline completer's 1318 idea of word break characters. 1319 1320d. The `type' builtin no longer reports on aliases unless alias expansion 1321 will actually be performed. 1322 1323e. HISTCONTROL is now a colon-separated list of values, which permits 1324 more extensibility and backwards compatibility. 1325 1326f. HISTCONTROL may now include the `erasedups' option, which causes all lines 1327 matching a line being added to be removed from the history list. 1328 1329g. `configure' has a new `--enable-multibyte' argument that permits multibyte 1330 character support to be disabled even on systems that support it. 1331 1332h. New variables to support the bash debugger: BASH_ARGC, BASH_ARGV, 1333 BASH_SOURCE, BASH_LINENO, BASH_SUBSHELL, BASH_EXECUTION_STRING, 1334 BASH_COMMAND 1335 1336i. FUNCNAME has been changed to support the debugger: it's now an array 1337 variable. 1338 1339j. for, case, select, arithmetic commands now keep line number information 1340 for the debugger. 1341 1342k. There is a new `RETURN' trap executed when a function or sourced script 1343 returns (not inherited child processes; inherited by command substitution 1344 if function tracing is enabled and the debugger is active). 1345 1346l. New invocation option: --debugger. Enables debugging and turns on new 1347 `extdebug' shell option. 1348 1349m. New `functrace' and `errtrace' options to `set -o' cause DEBUG and ERR 1350 traps, respectively, to be inherited by shell functions. Equivalent to 1351 `set -T' and `set -E' respectively. The `functrace' option also controls 1352 whether or not the DEBUG trap is inherited by sourced scripts. 1353 1354n. The DEBUG trap is run before binding the variable and running the action 1355 list in a `for' command, binding the selection variable and running the 1356 query in a `select' command, and before attempting a match in a `case' 1357 command. 1358 1359o. New `--enable-debugger' option to `configure' to compile in the debugger 1360 support code. 1361 1362p. `declare -F' now prints out extra line number and source file information 1363 if the `extdebug' option is set. 1364 1365q. If `extdebug' is enabled, a non-zero return value from a DEBUG trap causes 1366 the next command to be skipped, and a return value of 2 while in a 1367 function or sourced script forces a `return'. 1368 1369r. New `caller' builtin to provide a call stack for the bash debugger. 1370 1371s. The DEBUG trap is run just before the first command in a function body is 1372 executed, for the debugger. 1373 1374t. `for', `select', and `case' command heads are printed when `set -x' is 1375 enabled. 1376 1377u. There is a new {x..y} brace expansion, which is shorthand for {x.x+1, 1378 x+2,...,y}. x and y can be integers or single characters; the sequence 1379 may ascend or descend; the increment is always 1. 1380 1381v. New ksh93-like ${!array[@]} expansion, expands to all the keys (indices) 1382 of array. 1383 1384w. New `force_fignore' shopt option; if enabled, suffixes specified by 1385 FIGNORE cause words to be ignored when performing word completion even 1386 if they're the only possibilities. 1387 1388x. New `gnu_errfmt' shopt option; if enabled, error messages follow the `gnu 1389 style' (filename:lineno:message) format. 1390 1391y. New `-o bashdefault' option to complete and compgen; if set, causes the 1392 whole set of bash completions to be performed if the compspec doesn't 1393 result in a match. 1394 1395z. New `-o plusdirs' option to complete and compgen; if set, causes directory 1396 name completion to be performed and the results added to the rest of the 1397 possible completions. 1398 1399aa. `kill' is available as a builtin even when the shell is built without 1400 job control. 1401 1402bb. New HISTTIMEFORMAT variable; value is a format string to pass to 1403 strftime(3). If set and not null, the `history' builtin prints out 1404 timestamp information according to the specified format when displaying 1405 history entries. If set, bash tells the history library to write out 1406 timestamp information when the history file is written. 1407 1408cc. The [[ ... ]] command has a new binary `=~' operator that performs 1409 extended regular expression (egrep-like) matching. 1410 1411dd. `configure' has a new `--enable-cond-regexp' option (enabled by default) 1412 to enable the =~ operator and regexp matching in [[ ... ]]. 1413 1414ee. Subexpressions matched by the =~ operator are placed in the new 1415 BASH_REMATCH array variable. 1416 1417ff. New `failglob' option that causes an expansion error when pathname 1418 expansion fails to produce a match. 1419 1420gg. New `set -o pipefail' option that causes a pipeline to return a failure 1421 status if any of the processes in the pipeline fail, not just the last 1422 one. 1423 1424hh. printf builtin understands two new escape sequences: \" and \?. 1425 1426ii. `echo -e' understands two new escape sequences: \" and \?. 1427 1428jj. The GNU `gettext' package and libintl have been integrated; the shell's 1429 messages can be translated into different languages. 1430 1431kk. The `\W' prompt expansion now abbreviates $HOME as `~', like `\w'. 1432 1433ll. The error message printed when bash cannot open a shell script supplied 1434 as argument 1 now includes the name of the shell, to better identify 1435 the error as coming from bash. 1436 1437mm. The parameter pattern removal and substitution expansions are now much 1438 faster and more efficient when using multibyte characters. 1439 1440nn. The `jobs', `kill', and `wait' builtins now accept job control notation 1441 even if job control is not enabled. 1442 1443oo. The historical behavior of `trap' that allows a missing `action' argument 1444 to cause each specified signal's handling to be reset to its default is 1445 now only supported when `trap' is given a single non-option argument. 1446 14472. New Features in Readline 1448 1449a. History expansion has a new `a' modifier equivalent to the `g' modifier 1450 for compatibility with the BSD csh. 1451 1452b. History expansion has a new `G' modifier equivalent to the BSD csh `g' 1453 modifier, which performs a substitution once per word. 1454 1455c. All non-incremental search operations may now undo the operation of 1456 replacing the current line with the history line. 1457 1458d. The text inserted by an `a' command in vi mode can be reinserted with 1459 `.'. 1460 1461e. New bindable variable, `show-all-if-unmodified'. If set, the readline 1462 completer will list possible completions immediately if there is more 1463 than one completion and partial completion cannot be performed. 1464 1465f. There is a new application-callable `free_history_entry()' function. 1466 1467g. History list entries now contain timestamp information; the history file 1468 functions know how to read and write timestamp information associated 1469 with each entry. 1470 1471h. Four new key binding functions have been added: 1472 1473 rl_bind_key_if_unbound() 1474 rl_bind_key_if_unbound_in_map() 1475 rl_bind_keyseq_if_unbound() 1476 rl_bind_keyseq_if_unbound_in_map() 1477 1478i. New application variable, rl_completion_quote_character, set to any 1479 quote character readline finds before it calls the application completion 1480 function. 1481 1482j. New application variable, rl_completion_suppress_quote, settable by an 1483 application completion function. If set to non-zero, readline does not 1484 attempt to append a closing quote to a completed word. 1485 1486k. New application variable, rl_completion_found_quote, set to a non-zero 1487 value if readline determines that the word to be completed is quoted. 1488 Set before readline calls any application completion function. 1489 1490l. New function hook, rl_completion_word_break_hook, called when readline 1491 needs to break a line into words when completion is attempted. Allows 1492 the word break characters to vary based on position in the line. 1493 1494m. New bindable command: unix-filename-rubout. Does the same thing as 1495 unix-word-rubout, but adds `/' to the set of word delimiters. 1496 1497n. When listing completions, directories have a `/' appended if the 1498 `mark-directories' option has been enabled. 1499 1500------------------------------------------------------------------------------- 1501This is a terse description of the new features added to bash-2.05b since 1502the release of bash-2.05a. As always, the manual page (doc/bash.1) is 1503the place to look for complete descriptions. 1504 15051. New Features in Bash 1506 1507a. If set, TMOUT is the default timeout for the `read' builtin. 1508 1509b. `type' has two new options: `-f' suppresses shell function lookup, and 1510 `-P' forces a $PATH search. 1511 1512c. New code to handle multibyte characters. 1513 1514d. `select' was changed to be more ksh-compatible, in that the menu is 1515 reprinted each time through the loop only if REPLY is set to NULL. 1516 The previous behavior is available as a compile-time option. 1517 1518e. `complete -d' and `complete -o dirnames' now force a slash to be 1519 appended to names which are symlinks to directories. 1520 1521f. There is now a bindable edit-and-execute-command readline command, 1522 like the vi-mode `v' command, bound to C-xC-e in emacs mode. 1523 1524g. Added support for ksh93-like [:word:] character class in pattern matching. 1525 1526h. The $'...' quoting construct now expands \cX to Control-X. 1527 1528i. A new \D{...} prompt expansion; passes the `...' to strftime and inserts 1529 the result into the expanded prompt. 1530 1531j. The shell now performs arithmetic in the largest integer size the 1532 machine supports (intmax_t), instead of long. 1533 1534k. If a numeric argument is supplied to one of the bash globbing completion 1535 functions, a `*' is appended to the word before expansion is attempted. 1536 1537l. The bash globbing completion functions now allow completions to be listed 1538 with double tabs or if `show-all-if-ambiguous' is set. 1539 1540m. New `-o nospace' option for `complete' and `compgen' builtins; suppresses 1541 readline's appending a space to the completed word. 1542 1543n. New `here-string' redirection operator: <<< word. 1544 1545o. When displaying variables, function attributes and definitions are shown 1546 separately, allowing them to be re-used as input (attempting to re-use 1547 the old output would result in syntax errors). 1548 1549p. There is a new configuration option `--enable-mem-scramble', controls 1550 bash malloc behavior of writing garbage characters into memory at 1551 allocation and free time. 1552 1553q. The `complete' and `compgen' builtins now have a new `-s/-A service' 1554 option to complete on names from /etc/services. 1555 1556r. `read' has a new `-u fd' option to read from a specified file descriptor. 1557 1558s. Fix the completion code so that expansion errors in a directory name 1559 don't cause a longjmp back to the command loop. 1560 1561t. Fixed word completion inside command substitution to work a little more 1562 intuitively. 1563 1564u. The `printf' %q format specifier now uses $'...' quoting to print the 1565 argument if it contains non-printing characters. 1566 1567v. The `declare' and `typeset' builtins have a new `-t' option. When applied 1568 to functions, it causes the DEBUG trap to be inherited by the named 1569 function. Currently has no effect on variables. 1570 1571w. The DEBUG trap is now run *before* simple commands, ((...)) commands, 1572 [[...]] conditional commands, and for ((...)) loops. 1573 1574x. The expansion of $LINENO inside a shell function is only relative to the 1575 function start if the shell is interactive -- if the shell is running a 1576 script, $LINENO expands to the line number in the script. This is as 1577 POSIX-2001 requires. 1578 1579y. The bash debugger in examples/bashdb has been modified to work with the 1580 new DEBUG trap semantics, the command set has been made more gdb-like, 1581 and the changes to $LINENO make debugging functions work better. Code 1582 from Gary Vaughan. 1583 1584z. New [n]<&word- and [n]>&word- redirections from ksh93 -- move fds (dup 1585 and close). 1586 1587aa. There is a new `-l' invocation option, equivalent to `--login'. 1588 1589bb. The `hash' builtin has a new `-l' option to list contents in a reusable 1590 format, and a `-d' option to remove a name from the hash table. 1591 1592cc. There is now support for placing the long help text into separate files 1593 installed into ${datadir}/bash. Not enabled by default; can be turned 1594 on with `--enable-separate-helpfiles' option to configure. 1595 1596dd. All builtins that take operands accept a `--' pseudo-option, except 1597 `echo'. 1598 1599ee. The `echo' builtin now accepts \0xxx (zero to three octal digits following 1600 the `0') in addition to \xxx (one to three octal digits) for SUSv3/XPG6/ 1601 POSIX.1-2001 compliance. 1602 1603 16042. New Features in Readline 1605 1606a. Support for key `subsequences': allows, e.g., ESC and ESC-a to both 1607 be bound to readline functions. Now the arrow keys may be used in vi 1608 insert mode. 1609 1610b. When listing completions, and the number of lines displayed is more than 1611 the screen length, readline uses an internal pager to display the results. 1612 This is controlled by the `page-completions' variable (default on). 1613 1614c. New code to handle editing and displaying multibyte characters. 1615 1616d. The behavior introduced in bash-2.05a of deciding whether or not to 1617 append a slash to a completed name that is a symlink to a directory has 1618 been made optional, controlled by the `mark-symlinked-directories' 1619 variable (default is the 2.05a behavior). 1620 1621e. The `insert-comment' command now acts as a toggle if given a numeric 1622 argument: if the first characters on the line don't specify a 1623 comment, insert one; if they do, delete the comment text 1624 1625f. New application-settable completion variable: 1626 rl_completion_mark_symlink_dirs, allows an application's completion 1627 function to temporarily override the user's preference for appending 1628 slashes to names which are symlinks to directories. 1629 1630g. New function available to application completion functions: 1631 rl_completion_mode, to tell how the completion function was invoked 1632 and decide which argument to supply to rl_complete_internal (to list 1633 completions, etc.). 1634 1635h. Readline now has an overwrite mode, toggled by the `overwrite-mode' 1636 bindable command, which could be bound to `Insert'. 1637 1638i. New application-settable completion variable: 1639 rl_completion_suppress_append, inhibits appending of 1640 rl_completion_append_character to completed words. 1641 1642j. New key bindings when reading an incremental search string: ^W yanks 1643 the currently-matched word out of the current line into the search 1644 string; ^Y yanks the rest of the current line into the search string, 1645 DEL or ^H deletes characters from the search string. 1646 1647------------------------------------------------------------------------------- 1648This is a terse description of the new features added to bash-2.05a since 1649the release of bash-2.05. As always, the manual page (doc/bash.1) is 1650the place to look for complete descriptions. 1651 16521. New Features in Bash 1653 1654a. Added support for DESTDIR installation root prefix, so you can do a 1655 `make install DESTDIR=bash-root' and do easier binary packaging. 1656 1657b. Added support for builtin printf "'" flag character as per latest POSIX 1658 drafts. 1659 1660c. Support for POSIX.2 printf(1) length specifiers `j', `t', and `z' (from 1661 ISO C99). 1662 1663d. New autoconf macro, RL_LIB_READLINE_VERSION, for use by other applications 1664 (bash doesn't use very much of what it returns). 1665 1666e. `set [-+]o nolog' is recognized as required by the latest POSIX drafts, 1667 but ignored. 1668 1669f. New read-only `shopt' option: login_shell. Set to non-zero value if the 1670 shell is a login shell. 1671 1672g. New `\A' prompt string escape sequence; expands to time in 24 HH:MM format. 1673 1674h. New `-A group/-g' option to complete and compgen; does group name 1675 completion. 1676 1677i. New `-t' option to `hash' to list hash values for each filename argument. 1678 1679j. New [-+]O invocation option to set and unset `shopt' options at startup. 1680 1681k. configure's `--with-installed-readline' option now takes an optional 1682 `=PATH' suffix to set the root of the tree where readline is installed 1683 to PATH. 1684 1685l. The ksh-like `ERR' trap has been added. The `ERR' trap will be run 1686 whenever the shell would have exited if the -e option were enabled. 1687 It is not inherited by shell functions. 1688 1689m. `readonly', `export', and `declare' now print variables which have been 1690 given attributes but not set by assigning a value as just a command and 1691 a variable name (like `export foo') when listing, as the latest POSIX 1692 drafts require. 1693 1694n. `bashbug' now requires that the subject be changed from the default. 1695 1696o. configure has a new `--enable-largefile' option, like other GNU utilities. 1697 1698p. `for' loops now allow empty word lists after `in', like the latest POSIX 1699 drafts require. 1700 1701q. The builtin `ulimit' now takes two new non-numeric arguments: `hard', 1702 meaning the current hard limit, and `soft', meaning the current soft 1703 limit, in addition to `unlimited' 1704 1705r. `ulimit' now prints the option letter associated with a particular 1706 resource when printing more than one limit. 1707 1708s. `ulimit' prints `hard' or `soft' when a value is not `unlimited' but is 1709 one of RLIM_SAVED_MAX or RLIM_SAVED_CUR, respectively. 1710 1711t. The `printf' builtin now handles the %a and %A conversions if they're 1712 implemented by printf(3). 1713 1714u. The `printf' builtin now handles the %F conversion (just about like %f). 1715 1716v. The `printf' builtin now handles the %n conversion like printf(3). The 1717 corresponding argument is the name of a shell variable to which the 1718 value is assigned. 1719 17202. New Features in Readline 1721 1722a. Added extern declaration for rl_get_termcap to readline.h, making it a 1723 public function (it was always there, just not in readline.h). 1724 1725b. New #defines in readline.h: RL_READLINE_VERSION, currently 0x0402, 1726 RL_VERSION_MAJOR, currently 4, and RL_VERSION_MINOR, currently 2. 1727 1728c. New readline variable: rl_readline_version, mirrors RL_READLINE_VERSION. 1729 1730d. New bindable boolean readline variable: match-hidden-files. Controls 1731 completion of files beginning with a `.' (on Unix). Enabled by default. 1732 1733e. The history expansion code now allows any character to terminate a 1734 `:first-' modifier, like csh. 1735 1736f. New bindable variable `history-preserve-point'. If set, the history 1737 code attempts to place the user at the same location on each history 1738 line retrieved with previous-history or next-history. 1739 1740------------------------------------------------------------------------------- 1741This is a terse description of the new features added to bash-2.05 since 1742the release of bash-2.04. As always, the manual page (doc/bash.1) is 1743the place to look for complete descriptions. 1744 17451. New Features in Bash 1746 1747a. Added a new `--init-file' invocation argument as a synonym for `--rcfile', 1748 per the new GNU coding standards. 1749 1750b. The /dev/tcp and /dev/udp redirections now accept service names as well as 1751 port numbers. 1752 1753c. `complete' and `compgen' now take a `-o value' option, which controls some 1754 of the aspects of that compspec. Valid values are: 1755 1756 default - perform bash default completion if programmable 1757 completion produces no matches 1758 dirnames - perform directory name completion if programmable 1759 completion produces no matches 1760 filenames - tell readline that the compspec produces filenames, 1761 so it can do things like append slashes to 1762 directory names and suppress trailing spaces 1763 1764d. A new loadable builtin, realpath, which canonicalizes and expands symlinks 1765 in pathname arguments. 1766 1767e. When `set' is called without options, it prints function definitions in a 1768 way that allows them to be reused as input. This affects `declare' and 1769 `declare -p' as well. This only happens when the shell is not in POSIX 1770 mode, since POSIX.2 forbids this behavior. 1771 1772f. Bash-2.05 once again honors the current locale setting when processing 1773 ranges within pattern matching bracket expressions (e.g., [A-Z]). 1774 17752. New Features in Readline 1776 1777a. The blink timeout for paren matching is now settable by applications, 1778 via the rl_set_paren_blink_timeout() function. 1779 1780b. _rl_executing_macro has been renamed to rl_executing_macro, which means 1781 it's now part of the public interface. 1782 1783c. Readline has a new variable, rl_readline_state, which is a bitmap that 1784 encapsulates the current state of the library; intended for use by 1785 callbacks and hook functions. 1786 1787d. New application-callable function rl_set_prompt(const char *prompt): 1788 expands its prompt string argument and sets rl_prompt to the result. 1789 1790e. New application-callable function rl_set_screen_size(int rows, int cols): 1791 public method for applications to set readline's idea of the screen 1792 dimensions. 1793 1794f. New function, rl_get_screen_size (int *rows, int *columns), returns 1795 readline's idea of the screen dimensions. 1796 1797g. The timeout in rl_gather_tyi (readline keyboard input polling function) 1798 is now settable via a function (rl_set_keyboard_input_timeout()). 1799 1800h. Renamed the max_input_history variable to history_max_entries; the old 1801 variable is maintained for backwards compatibility. 1802 1803i. The list of characters that separate words for the history tokenizer is 1804 now settable with a variable: history_word_delimiters. The default 1805 value is as before. 1806 1807------------------------------------------------------------------------------- 1808This is a terse description of the new features added to bash-2.04 since 1809the release of bash-2.03. As always, the manual page (doc/bash.1) is 1810the place to look for complete descriptions. 1811 18121. New Features in Bash 1813 1814a. The history builtin has a `-d offset' option to delete the history entry 1815 at position `offset'. 1816 1817b. The prompt expansion code has two new escape sequences: \j, the number of 1818 active jobs; and \l, the basename of the shell's tty device name. 1819 1820c. The `bind' builtin has a new `-x' option to bind key sequences to shell 1821 commands. 1822 1823d. There is a new shell option, no_empty_command_completion, which, when 1824 enabled, disables command completion when TAB is typed on an empty line. 1825 1826e. The `help' builtin has a `-s' option to just print a builtin's usage 1827 synopsis. 1828 1829f. There are several new arithmetic operators: id++, id-- (variable 1830 post-increment/decrement), ++id, --id (variable pre-increment/decrement), 1831 expr1 , expr2 (comma operator). 1832 1833g. There is a new ksh-93 style arithmetic for command: 1834 for ((expr1 ; expr2; expr3 )); do list; done 1835 1836h. The `read' builtin has a number of new options: 1837 -t timeout only wait timeout seconds for input 1838 -n nchars only read nchars from input instead of a full line 1839 -d delim read until delim rather than newline 1840 -s don't echo input chars as they are read 1841 1842i. The redirection code now handles several filenames specially: 1843 /dev/fd/N, /dev/stdin, /dev/stdout, and /dev/stderr, whether or 1844 not they are present in the file system. 1845 1846j. The redirection code now recognizes pathnames of the form 1847 /dev/tcp/host/port and /dev/udp/host/port, and tries to open a socket 1848 of the appropriate type to the specified port on the specified host. 1849 1850k. The ksh-93 ${!prefix*} expansion, which expands to the names of all 1851 shell variables with prefix PREFIX, has been implemented. 1852 1853l. There is a new dynamic variable, FUNCNAME, which expands to the name of 1854 a currently-executing function. Assignments to FUNCNAME have no effect. 1855 1856m. The GROUPS variable is no longer readonly; assignments to it are silently 1857 discarded. This means it can be unset. 1858 1859n. A new programmable completion facility, with two new builtin commands: 1860 complete and compgen. 1861 1862o. configure has a new option, `--enable-progcomp', to compile in the 1863 programmable completion features (enabled by default). 1864 1865p. `shopt' has a new option, `progcomp', to enable and disable programmable 1866 completion at runtime. 1867 1868q. Unsetting HOSTFILE now clears the list of hostnames used for completion. 1869 1870r. configure has a new option, `--enable-bash-malloc', replacing the old 1871 `--with-gnu-malloc' (which is still present for backwards compatibility). 1872 1873s. There is a new manual page describing rbash, the restricted shell. 1874 1875t. `bashbug' has new `--help' and `--version' options. 1876 1877u. `shopt' has a new `xpg_echo' option, which controls the behavior of 1878 `echo' with respect to backslash-escaped characters at runtime. 1879 1880v. If NON_INTERACTIVE_LOGIN_SHELLS is defined, all login shells read the 1881 startup files, even if they are not interactive. 1882 1883w. The LC_NUMERIC variable is now treated specially, and used to set the 1884 LC_NUMERIC locale category for number formatting, e.g., when `printf' 1885 displays floating-point numbers. 1886 18872. New features in Readline 1888 1889a. Parentheses matching is now always compiled into readline, and enabled 1890 or disabled when the value of the `blink-matching-paren' variable is 1891 changed. 1892 1893b. MS-DOS systems now use ~/_inputrc as the last-ditch inputrc filename. 1894 1895c. MS-DOS systems now use ~/_history as the default history file. 1896 1897d. history-search-{forward,backward} now leave the point at the end of the 1898 line when the string to search for is empty, like 1899 {reverse,forward}-search-history. 1900 1901e. history-search-{forward,backward} now leave the last history line found 1902 in the readline buffer if the second or subsequent search fails. 1903 1904f. New function for use by applications: rl_on_new_line_with_prompt, used 1905 when an application displays the prompt itself before calling readline(). 1906 1907g. New variable for use by applications: rl_already_prompted. An application 1908 that displays the prompt itself before calling readline() must set this to 1909 a non-zero value. 1910 1911h. A new variable, rl_gnu_readline_p, always 1. The intent is that an 1912 application can verify whether or not it is linked with the `real' 1913 readline library or some substitute. 1914 1915------------------------------------------------------------------------------- 1916This is a terse description of the new features added to bash-2.03 since 1917the release of bash-2.02. As always, the manual page (doc/bash.1) is 1918the place to look for complete descriptions. 1919 19201. New Features in Bash 1921 1922a. New `shopt' option, `restricted_shell', indicating whether or not the 1923 shell was started in restricted mode, for use in startup files. 1924 1925b. Filename generation is now performed on the words between ( and ) in 1926 array assignments (which it probably should have done all along). 1927 1928c. OLDPWD is now auto-exported, as POSIX.2 seems to require. 1929 1930d. ENV and BASH_ENV are read-only variables in a restricted shell. 1931 1932e. A change was made to the startup file code so that any shell begun with 1933 the `--login' option, even non-interactive shells, will source the login 1934 shell startup files. 1935 19362. New Features in Readline 1937 1938a. Many changes to the signal handling: 1939 o Readline now catches SIGQUIT and cleans up the tty before returning; 1940 o A new variable, rl_catch_signals, is available to application writers 1941 to indicate to readline whether or not it should install its own 1942 signal handlers for SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP, 1943 SIGTTIN, and SIGTTOU; 1944 o A new variable, rl_catch_sigwinch, is available to application 1945 writers to indicate to readline whether or not it should install its 1946 own signal handler for SIGWINCH, which will chain to the calling 1947 applications's SIGWINCH handler, if one is installed; 1948 o There is a new function, rl_free_line_state, for application signal 1949 handlers to call to free up the state associated with the current 1950 line after receiving a signal; 1951 o There is a new function, rl_cleanup_after_signal, to clean up the 1952 display and terminal state after receiving a signal; 1953 o There is a new function, rl_reset_after_signal, to reinitialize the 1954 terminal and display state after an application signal handler 1955 returns and readline continues 1956 1957b. There is a new function, rl_resize_terminal, to reset readline's idea of 1958 the screen size after a SIGWINCH. 1959 1960c. New public functions: rl_save_prompt and rl_restore_prompt. These were 1961 previously private functions with a `_' prefix. 1962 1963d. New function hook: rl_pre_input_hook, called just before readline starts 1964 reading input, after initialization. 1965 1966e. New function hook: rl_display_matches_hook, called when readline would 1967 display the list of completion matches. The new function 1968 rl_display_match_list is what readline uses internally, and is available 1969 for use by application functions called via this hook. 1970 1971f. New bindable function, delete-char-or-list, like tcsh. 1972 1973g. A new variable, rl_erase_empty_line, which, if set by an application using 1974 readline, will cause readline to erase, prompt and all, lines on which the 1975 only thing typed was a newline. 1976 1977h. New bindable variable: `isearch-terminators'. 1978 1979i. New bindable function: `forward-backward-delete-char' (unbound by default). 1980 1981------------------------------------------------------------------------------- 1982This is a terse description of the new features added to bash-2.02 since 1983the release of bash-2.01.1. As always, the manual page (doc/bash.1) is 1984the place to look for complete descriptions. 1985 19861. New Features in Bash 1987 1988a. A new version of malloc, based on the older GNU malloc, that has many 1989 changes, is more page-based, is more conservative with memory usage, 1990 and does not `orphan' large blocks when they are freed. 1991 1992b. A new version of gmalloc, based on the old GLIBC malloc, with many 1993 changes and range checking included by default. 1994 1995c. A new implementation of fnmatch(3) that includes full POSIX.2 Basic 1996 Regular Expression matching, including character classes, collating 1997 symbols, equivalence classes, and support for case-insensitive pattern 1998 matching. 1999 2000d. ksh-88 egrep-style extended pattern matching ([@+*?!](patlist)) has been 2001 implemented, controlled by a new `shopt' option, `extglob'. 2002 2003e. There is a new ksh-like `[[' compound command, which implements 2004 extended `test' functionality. 2005 2006f. There is a new `printf' builtin, implemented according to the POSIX.2 2007 specification. 2008 2009g. There is a new feature for command substitution: $(< filename) now expands 2010 to the contents of `filename', with any trailing newlines removed 2011 (equivalent to $(cat filename)). 2012 2013h. There are new tilde prefixes which expand to directories from the 2014 directory stack. 2015 2016i. There is a new `**' arithmetic operator to do exponentiation. 2017 2018j. There are new configuration options to control how bash is linked: 2019 `--enable-profiling', to allow bash to be profiled with gprof, and 2020 `--enable-static-link', to allow bash to be linked statically. 2021 2022k. There is a new configuration option, `--enable-cond-command', which 2023 controls whether or not the `[[' command is included. It is on by 2024 default. 2025 2026l. There is a new configuration option, `--enable-extended-glob', which 2027 controls whether or not the ksh extended globbing feature is included. 2028 It is enabled by default. 2029 2030m. There is a new configuration #define in config.h.top that, when enabled, 2031 will cause all login shells to source /etc/profile and one of the user- 2032 specific login shell startup files, whether or not the shell is 2033 interactive. 2034 2035n. There is a new invocation option, `--dump-po-strings', to dump 2036 a shell script's translatable strings ($"...") in GNU `po' format. 2037 2038o. There is a new `shopt' option, `nocaseglob', to enable case-insensitive 2039 pattern matching when globbing filenames and using the `case' construct. 2040 2041p. There is a new `shopt' option, `huponexit', which, when enabled, causes 2042 the shell to send SIGHUP to all jobs when an interactive login shell 2043 exits. 2044 2045q. `bind' has a new `-u' option, which takes a readline function name as an 2046 argument and unbinds all key sequences bound to that function in a 2047 specified keymap. 2048 2049r. `disown' now has `-a' and `-r' options, to limit operation to all jobs 2050 and running jobs, respectively. 2051 2052s. The `shopt' `-p' option now causes output to be displayed in a reusable 2053 format. 2054 2055t. `test' has a new `-N' option, which returns true if the filename argument 2056 has been modified since it was last accessed. 2057 2058u. `umask' now has a `-p' option to print output in a reusable format. 2059 2060v. A new escape sequence, `\xNNN', has been added to the `echo -e' and $'...' 2061 translation code. It expands to the character whose ascii code is NNN 2062 in hexadecimal. 2063 2064w. The prompt string expansion code has a new `\r' escape sequence. 2065 2066x. The shell may now be cross-compiled for the CYGWIN32 environment on 2067 a Unix machine. 2068 20692. New Features in Readline 2070 2071a. There is now an option for `iterative' yank-last-arg handline, so a user 2072 can keep entering `M-.', yanking the last argument of successive history 2073 lines. 2074 2075b. New variable, `print-completions-horizontally', which causes completion 2076 matches to be displayed across the screen (like `ls -x') rather than up 2077 and down the screen (like `ls'). 2078 2079c. New variable, `completion-ignore-case', which causes filename completion 2080 and matching to be performed case-insensitively. 2081 2082d. There is a new bindable command, `magic-space', which causes history 2083 expansion to be performed on the current readline buffer and a space to 2084 be inserted into the result. 2085 2086e. There is a new bindable command, `menu-complete', which enables tcsh-like 2087 menu completion (successive executions of menu-complete insert a single 2088 completion match, cycling through the list of possible completions). 2089 2090f. There is a new bindable command, `paste-from-clipboard', for use on Win32 2091 systems, to insert the text from the Win32 clipboard into the editing 2092 buffer. 2093 2094g. The key sequence translation code now understands printf-style backslash 2095 escape sequences, including \NNN octal escapes. These escape sequences 2096 may be used in key sequence definitions or macro values. 2097 2098h. An `$include' inputrc file parser directive has been added. 2099 2100------------------------------------------------------------------------------- 2101This is a terse description of the new features added to bash-2.01 since 2102the release of bash-2.0. As always, the manual page (doc/bash.1) is the 2103place to look for complete descriptions. 2104 21051. New Features in Bash 2106 2107a. There is a new builtin array variable: GROUPS, the set of groups to which 2108 the user belongs. This is used by the test suite. 2109 21102. New Features in Readline 2111 2112a. If a key sequence bound to `universal-argument' is read while reading a 2113 numeric argument started with `universal-argument', it terminates the 2114 argument but is otherwise ignored. This provides a way to insert multiple 2115 instances of a digit string, and is how GNU emacs does it. 2116 2117------------------------------------------------------------------------------- 2118This is a terse description of the new features added to bash-2.0 since 2119the release of bash-1.14.7. As always, the manual page (doc/bash.1) is 2120the place to look for complete descriptions. 2121 21221. New Features in Bash 2123 2124a. There is a new invocation option, -D, that dumps translatable strings 2125 in a script. 2126 2127b. The `long' invocation options must now be prefixed with `--'. 2128 2129c. New long invocation options: --dump-strings, --help, --verbose 2130 2131d. The `nolineediting' invocation option was renamed to `noediting'. 2132 2133e. The `nobraceexpansion' and `quiet' long invocation options were removed. 2134 2135f. The `--help' and `--version' long options now work as the GNU coding 2136 standards specify. 2137 2138g. If invoked as `sh', bash now enters posix mode after reading the 2139 startup files, and reads and executes commands from the file named 2140 by $ENV if interactive (as POSIX.2 specifies). A login shell invoked 2141 as `sh' reads $ENV after /etc/profile and ~/.profile. 2142 2143h. There is a new reserved word, `time', for timing pipelines, builtin 2144 commands, and shell functions. It uses the value of the TIMEFORMAT 2145 variable as a format string describing how to print the timing 2146 statistics. 2147 2148i. The $'...' quoting syntax expands ANSI-C escapes in ... and leaves the 2149 result single-quoted. 2150 2151j. The $"..." quoting syntax performs locale-specific translation of ... 2152 and leaves the result double-quoted. 2153 2154k. LINENO now works correctly in functions. 2155 2156l. New variables: DIRSTACK, PIPESTATUS, BASH_VERSINFO, HOSTNAME, SHELLOPTS, 2157 MACHTYPE. The first three are array variables. 2158 2159m. The BASH_VERSION and BASH_VERSINFO variables now include the shell's 2160 `release status' (alpha[N], beta[N], release). 2161 2162n. Some variables have been removed: MAIL_WARNING, notify, history_control, 2163 command_oriented_history, glob_dot_filenames, allow_null_glob_expansion, 2164 nolinks, hostname_completion_file, noclobber, no_exit_on_failed_exec, and 2165 cdable_vars. Most of them are now implemented with the new `shopt' 2166 builtin; others were already implemented by `set'. 2167 2168o. Bash now uses some new variables: LC_ALL, LC_MESSAGES, LC_CTYPE, 2169 LC_COLLATE, LANG, GLOBIGNORE, HISTIGNORE. 2170 2171p. The shell now supports integer-indexed arrays of unlimited length, 2172 with a new compound assignment syntax and changes to the appropriate 2173 builtin commands (declare/typeset, read, readonly, etc.). The array 2174 index may be an arithmetic expression. 2175 2176q. ${!var}: indirect variable expansion, equivalent to eval \${$var}. 2177 2178r. ${parameter:offset[:length]}: variable substring extraction. 2179 2180s. ${parameter/pattern[/[/]string]}: variable pattern substitution. 2181 2182t. The $[...] arithmetic expansion syntax is no longer supported, in 2183 favor of $((...)). 2184 2185u. Aliases can now be expanded in shell scripts with a shell option 2186 (shopt expand_aliases). 2187 2188v. History and history expansion can now be used in scripts with 2189 set -o history and set -H. 2190 2191w. All builtins now return an exit status of 2 for incorrect usage. 2192 2193x. Interactive shells resend SIGHUP to all running or stopped children 2194 if (and only if) they exit due to a SIGHUP. 2195 2196y. New prompting expansions: \a, \e, \H, \T, \@, \v, \V. 2197 2198z. Variable expansion in prompt strings is now controllable via a shell 2199 option (shopt promptvars). 2200 2201aa. Bash now defaults to using command-oriented history. 2202 2203bb. The history file ($HISTFILE) is now truncated to $HISTFILESIZE after 2204 being written. 2205 2206cc. The POSIX.2 conditional arithmetic evaluation syntax (expr ? expr : expr) 2207 has been implemented. 2208 2209dd. Each builtin now accepts `--' to signify the end of the options, except 2210 as documented (echo, etc.). 2211 2212ee. All builtins use -p to display values in a re-readable format where 2213 appropriate, except as documented (echo, type, etc.). 2214 2215ff. The `alias' builtin has a new -p option. 2216 2217gg. Changes to the `bind' builtin: 2218 o has new options: -psPSVr. 2219 o the `-d' option was renamed to `-p' 2220 o the `-v' option now dumps variables; the old `-v' is now `-P' 2221 2222hh. The `bye' synonym for `exit' was removed. 2223 2224ii. The -L and -P options to `cd' and `pwd' have been documented. 2225 2226jj. The `cd' builtin now does spelling correction on the directory name 2227 by default. This is settable with a shell option (shopt cdspell). 2228 2229kk. The `declare' builtin has new options: -a, -F, -p. 2230 2231ll. The `dirs' builtin has new options: -c, -p, -v. 2232 2233mm. The new `disown' builtin removes jobs from the shell's jobs table 2234 or inhibits the resending of SIGHUP when the shell receives a 2235 SIGHUP. 2236 2237nn. The `echo' builtin has a new escape character: \e. 2238 2239oo. The `enable' builtin can now load new builtins dynamically from shared 2240 objects on systems with the dlopen/dlsym interface. There are a number 2241 of examples in the examples/loadables directory. There are also 2242 new options: -d, -f, -s, -p. 2243 2244pp. The `-all' option to `enable' was removed in favor of `-a'. 2245 2246qq. The `exec' builtin has new options: -l, -c, -a. 2247 2248rr. The `hash' builtin has a new option: -p. 2249 2250ss. The `history' builtin has new options: -c, -p, -s. 2251 2252tt. The `jobs' builtin has new options: -r, -s. 2253 2254uu. The `kill' builtin has new options: -n signum, -l signame. 2255 2256vv. The `pushd' and `popd' builtins have a new option: -n. 2257 2258ww. The `read' builtin has new options: -p prompt, -e, -a. 2259 2260xx. The `readonly' builtin has a new -a option, and the -n option was removed. 2261 2262yy. Changes to the `set' builtin: 2263 o new options: -B, -o keyword, -o onecmd, -o history 2264 o options removed: -l, -d, -o nohash 2265 o options changed: +o, -h, -o hashall 2266 o now displays variables in a format that can be re-read as input 2267 2268zz. The new `shopt' builtin controls shell optional behavior previously 2269 done by setting and unsetting certain shell variables. 2270 2271aaa. The `test' builtin has new operators: -o option, s1 == s2, s1 < s2, 2272 and s1 > s2, where s1 and s2 are strings. 2273 2274bbb. There is a new trap, DEBUG, executed after every simple command. 2275 2276ccc. The `trap' builtin has a new -p option. 2277 2278ddd. The `ulimit' builtin has a new -l option on 4.4BSD-based systems. 2279 2280eee. The PS1, PS2, PATH, and IFS variables may now be unset. 2281 2282fff. The restricted shell mode has been expanded and is now documented. 2283 2284ggg. Security improvements: 2285 o functions are not imported from the environment if running setuid 2286 or with -p 2287 o no startup files are sourced if running setuid or with -p 2288 2289hhh. The documentation has been overhauled: the texinfo manual was 2290 expanded, and HTML versions of the man page and texinfo manual 2291 are included. 2292 2293iii. Changes to Posix mode: 2294 o Command lookup now finds special builtins before shell functions. 2295 o Failure of a special builtin causes a non-interactive shell to 2296 exit. Failures are defined in the POSIX.2 specification. 2297 o If the `cd' builtin finds a directory to change to using $CDPATH, 2298 the value assigned to PWD when `cd' completes does not contain 2299 any symbolic links. 2300 o A non-interactive shell exits if a variable assignment error 2301 occurs when no command name follows the assignment statements. 2302 o A non-interactive shell exits if the iteration variable in a 2303 `for' statement or the selection variable in a `select' statement 2304 is read-only or another variable assignment error occurs. 2305 o The `<>' redirection operator now opens a file for both stdin and 2306 stdout by default, not just when in posix mode. 2307 o Assignment statements preceding special builtins now persist in 2308 the shell's environment when the builtin completes. 2309 2310 Posix mode is now completely POSIX.2-compliant (modulo bugs). When 2311 invoked as sh, bash should be completely POSIX.2-compliant. 2312 2313jjj. The default value of PS1 is now "\s-\v\$ ". 2314 2315kkk. The ksh-like ((...)) arithmetic command syntax has been implemented. 2316 This is exactly equivalent to `let "..."'. 2317 2318lll. Integer constants have been extended to base 64. 2319 2320mmm. The `ulimit' builtin now sets both hard and soft limits and reports the 2321 soft limit by default. 2322 23232. New Features in Readline 2324 2325a. New variables: enable-keypad, input-meta (new name for meta-flag), 2326 mark-directories, visible-stats (now documented), disable-completion, 2327 comment-begin. 2328 2329b. New bindable commands: kill-region, copy-region-as-kill, 2330 copy-backward-word, copy-forward-word, set-mark, exchange-point-and-mark, 2331 character-search, character-search-backward, insert-comment, 2332 glob-expand-word, glob-list-expansions, dump-variables, dump-macros. 2333 2334c. New emacs keybindings: delete-horizontal-space (M-\), 2335 insert-completions (M-*), possible-completions (M-=). 2336 2337d. The history-search-backward and history-search-forward commands were 2338 modified to be the same as previous-line and next-line if point is at 2339 the start of the line. 2340 2341e. More file types are available for the visible-stats mode. 2342 23433. Changes of interest in the Bash implementation 2344 2345a. There is a new autoconf-based configuration mechanism. 2346 2347b. More things have been moved from Posix mode to standard shell behavior. 2348 2349c. The trace output (set -x) now inserts quotes where necessary so it can 2350 be reused as input. 2351 2352d. There is a compile-time option for a system-wide interactive shell 2353 startup file (disabled by default). 2354 2355e. The YACC grammar is smaller and tighter, and all 66 shift-reduce 2356 conflicts are gone. Several parsing bugs have been fixed. 2357 2358f. Builtin option parsing has been regularized (using internal_getopt()), 2359 with the exception of `echo', `type', and `set'. 2360 2361g. Builtins now return standard usage messages constructed from the 2362 `short doc' used by the help builtin. 2363 2364h. Completion now quotes using backslashes by default, but honors 2365 user-supplied quotes. 2366 2367i. The GNU libc malloc is available as a configure-time option. 2368 2369j. There are more internationalization features; bash uses gettext if 2370 it is available. The $"..." translation syntax uses the current 2371 locale and gettext. 2372 2373k. There is better reporting of job termination when the shell is not 2374 interactive. 2375 2376l. The shell is somewhat more efficient: it uses a little less memory and 2377 makes fewer system calls. 2378 23794. Changes of interest in the Readline implementation 2380 2381a. There is now support for readline `callback' functions. 2382 2383b. There is now support for user-supplied input, redisplay, and terminal 2384 preparation functions. 2385 2386c. Most of the shell-specific code in readline has been generalized or 2387 removed. 2388 2389d. Most of the annoying redisplay bugs have been fixed, notably the problems 2390 with incremental search and excessive redrawing when special characters 2391 appear in the prompt string. 2392 2393e. There are new library functions and variables available to application 2394 writers, most having to do with completion and quoting. 2395 2396f. The NEWLINE character (^J) is now treated as a search terminator by the 2397 incremental search functions. 2398------------------------------------------------------------------------------- 2399 2400Copying and distribution of this file, with or without modification, 2401are permitted in any medium without royalty provided the copyright 2402notice and this notice are preserved. This file is offered as-is, 2403without any warranty. 2404