1.\" Copyright (c) 1983, 1990 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)telnet.1 6.13 (Berkeley) 07/28/90 7.\" 8.Dd 9.Dt TELNET 1 10.Os BSD 4.2 11.Sh NAME 12.Nm telnet 13.Nd user interface to the 14.Li TELNET 15protocol 16.Sh SYNOPSIS 17.Nm telnet 18.Op Fl d 19.Op Fl a 20.Op Fl n Ar tracefile 21.Op Fl e Ar escapechar 22.Ob 23.Op Fl l Ar user 24.Ar host 25.Op port 26.Oe 27.Sh DESCRIPTION 28The 29.Nm telnet 30command 31is used to communicate with another host using the 32.Li TELNET 33protocol. 34If 35.Nm telnet 36is invoked without the 37.Ar host 38argument, it enters command mode, 39indicated by its prompt 40.Pq Nm telnet\&> . 41In this mode, it accepts and executes the commands listed below. 42If it is invoked with arguments, it performs an 43.Ic open 44command with those arguments. 45.Pp 46Options: 47.Tw Fl 48.Tp Fl d 49Sets the initial value of the 50.Ic debug 51toggle to 52.Li TRUE 53.Tp Fl a 54Attempt automatic login. 55Currently, this sends the user name via the USER variable 56of the ENVIRON option if supported by the remote system. 57The name used is that of the current user as returned by 58.Xr getlogin 2 59if it agrees with the current user ID, 60otherwise it is the name associated with the user ID. 61.Tp Cx Fl n 62.Cx \&\ \& 63.Ar tracefile 64.Cx 65Opens 66.Ar tracefile 67for recording trace information. 68See the 69.Ic set tracefile 70command below. 71.Tp Cx Fl l 72.Cx \&\ \& 73.Ar user 74.Cx 75When connecting to the remote system, if the remote system 76understands the ENVIRON option, then 77.Ar user 78will be sent to the remote system as the value for the variable USER. 79This option implies the 80.Fl a 81option. 82This option may also be used with the 83.Ic open 84command. 85.Tp Cx Fl e 86.Cx \&\ \& 87.Ar escape char 88.Cx 89Sets the initial 90.Nm 91.B telnet 92escape character to 93.Ar escape char. 94If 95.Ar escape char 96is ommitted, then 97there will be no escape character. 98.Tp Ar host 99Indicates the official name, an alias, or the Internet address 100of a remote host. 101.Tp Ar port 102Indicates a port number (address of an application). If a number is 103not specified, the default 104.Nm telnet 105port is used. 106.Tp 107.Pp 108Once a connection has been opened, 109.Nm telnet 110will attempt to enable the 111.Li TELNET LINEMODE 112option. 113If this fails, then 114.Nm telnet 115will revert to one of two input modes: 116either \*(Lqcharacter at a time\*(Rq 117or \*(Lqold line by line\*(Rq 118depending on what the remote system supports. 119.Pp 120When 121.Li LINEMODE 122is enabled, character processing is done on the 123local system, under the control of the remote system. When input 124editing or character echoing is to be disabled, the remote system 125will relay that information. The remote system will also relay 126changes to any special characters that happen on the remote 127system, so that they can take effect on the local system. 128.Pp 129In \*(Lqcharacter at a time\*(Rq mode, most 130text typed is immediately sent to the remote host for processing. 131.Pp 132In \*(Lqold line by line\*(Rq mode, all text is echoed locally, 133and (normally) only completed lines are sent to the remote host. 134The \*(Lqlocal echo character\*(Rq (initially \*(Lq^E\*(Rq) may be used 135to turn off and on the local echo 136(this would mostly be used to enter passwords 137without the password being echoed). 138.Pp 139If the 140.Li LINEMODE 141option is enabled, or if the 142.Ic localchars 143toggle is TRUE (the default for \*(Lqold line by line\*(Lq; see below), 144the user's 145.Ic quit , 146.Ic intr , 147and 148.Ic flush 149characters are trapped locally, and sent as 150.Li TELNET 151protocol sequences to the remote side. 152If 153.Li LINEMODE 154has ever been enabled, then the user's 155.Ic susp 156and 157.Ic eof 158are also sent as 159.Li TELNET 160protocol sequences, 161and 162.Ic quit 163is sent as a 164.Li TELNET ABORT 165instead of 166.Li BREAK 167There are options (see 168.Ic toggle 169.Ic autoflush 170and 171.Ic toggle 172.Ic autosynch 173below) 174which cause this action to flush subsequent output to the terminal 175(until the remote host acknowledges the 176.Li TELNET 177sequence) and flush previous terminal input 178(in the case of 179.Ic quit 180and 181.Ic intr ) . 182.Pp 183While connected to a remote host, 184.Nm telnet 185command mode may be entered by typing the 186.Nm telnet 187\*(Lqescape character\*(Rq (initially \*(Lq^ 188\*(Rq). 189When in command mode, the normal terminal editing conventions are available. 190.Pp 191The following .Nm telnet 192commands are available. 193Only enough of each command to uniquely identify it need be typed 194(this is also true for arguments to the 195.Ic mode , 196.Ic set , 197.Ic toggle , 198.Ic unset , 199.Ic slc , 200.Ic environ , 201and 202.Ic display 203commands). 204.Pp 205.Tw Ic 206.Tp Ic close 207Close a 208.Li TELNET 209session and return to command mode. 210.Tp Cx Ic display 211.Cx \&\ \& 212.Ar argument ... 213.Cx 214Displays all, or some, of the 215.Ic set 216and 217.Ic toggle 218values (see below). 219.Tp Cx Ic mode 220.Cx \&\ \& 221.Ar type 222.Cx 223.Ar Type 224is one of several options, depending on the state of the 225.Li TELNET 226session. 227The remote host is asked for permission to go into the requested mode. 228If the remote host is capable of entering that mode, the requested 229mode will be entered. 230.Tw Ar 231.Tp Ic character 232Disable the 233.Li TELNET LINEMODE 234option, or, if the remote side does not understand the 235.Li LINEMODE 236option, then enter \*(Lqcharacter at a time\*(Lq mode. 237.Tp Ic line 238Enable the 239.Li TELNET LINEMODE 240option, or, if the remote side does not understand the 241.Li LINEMODE 242option, then attempt to enter \*(Lqold-line-by-line\*(Lq mode. 243.Tp Cx Ic isig 244.Cx \&\ \& 245.Pq Ic \-isig 246.Cx 247Attempt to enable (disable) the 248.Li TRAPSIG 249mode of the 250.Li LINEMODE 251option. 252This requires that the 253.Li LINEMODE 254option be enabled. 255.Tp Cx Ic edit 256.Cx \&\ \& 257.Pq Ic \-edit 258.Cx 259Attempt to enable (disable) the 260.Li EDIT 261mode of the 262.Li LINEMODE 263option. 264This requires that the 265.Li LINEMODE 266option be enabled. 267.Tp Cx Ic softtabs 268.Cx \&\ \& 269.Pq Ic \-softtabs 270.Cx 271Attempt to enable (disable) the 272.Li SOFT_TAB 273mode of the 274.Li LINEMODE 275option. 276This requires that the 277.Li LINEMODE 278option be enabled. 279.Tp Cx Ic litecho 280.Cx \&\ \& 281.Pq Ic \-litecho 282.Cx 283Attempt to enable (disable) the 284.Li LIT_ECHO 285mode of the 286.Li LINEMODE 287option. 288This requires that the 289.Li LINEMODE 290option be enabled. 291.Tp Ic \&? 292Prints out help information for the 293.Ic mode 294command. 295.Tp 296.Tp Cx Ic open 297.Cx \&\ \& 298.Ar host 299.Cx \&\ \& 300.Cx [ 301.Op Fl l 302.Cx \&\ \& 303.Ar user 304.Cx ] 305.Cx [ 306.Op Fl 307.Cx \&\ \& 308.Ar port 309.Cx ] 310.Cx 311Open a connection to the named host. 312If no port number 313is specified, 314.Nm telnet 315will attempt to contact a 316.Li TELNET 317server at the default port. 318The host specification may be either a host name (see 319.Xr hosts 5 ) 320or an Internet address specified in the \*(Lqdot notation\*(Rq (see 321.Xr inet 3 ) . 322The 323.Op Fl l 324option may be used to specify the user name 325to be passed to the remote system via the 326.Li ENVIRON 327option. 328When connecting to a non-standard port, 329.Nm telnet 330omits any automatic initiation of 331.Li TELNET 332options. When the port number is preceeded by a minus sign, 333the inital option negotiation is done. 334After establishing a connection, the file 335.Pa \&.telnetrc 336in the 337users home directory is opened. Lines begining with a # are 338comment lines. Blank lines are ignored. Lines that begin 339without whitespace are the start of a machine entry. The 340first thing on the line is the name of the machine that is 341being connected to. The rest of the line, and successive 342lines that begin with whitespace are assumed to be 343.Nm telnet 344commands and are processed as if they had been typed 345in manually to the 346.Nm telnet 347command prompt. 348.Tp Ic quit 349Close any open 350.Li TELNET 351session and exit 352.Nm telnet . 353An end of file (in command mode) will also close a session and exit. 354.Tp Cx Ic send 355.Cx \&\ \& 356.Ar arguments 357.Cx 358Sends one or more special character sequences to the remote host. 359The following are the arguments which may be specified 360(more than one argument may be specified at a time): 361.Pp 362.Tw Ds 363.Tp Ic abort 364Sends the 365.Li TELNET ABORT 366(ABORT processes) 367sequence. 368.Tp Ic ao 369Sends the 370.Li TELNET AO 371(Abort Output) sequence, which should cause the remote system to flush 372all output 373.Em from 374the remote system 375.Em to 376the user's terminal. 377.Tp Ic ayt 378Sends the 379.Li TELNET AYT 380(Are You There) 381sequence, to which the remote system may or may not choose to respond. 382.Tp Ic brk 383Sends the 384.Li TELNET BRK 385(Break) sequence, which may have significance to the remote 386system. 387.Tp Ic ec 388Sends the 389.Li TELNET EC 390(Erase Character) 391sequence, which should cause the remote system to erase the last character 392entered. 393.Tp Ic el 394Sends the 395.Li TELNET EL 396(Erase Line) 397sequence, which should cause the remote system to erase the line currently 398being entered. 399.Tp Ic eof 400Sends the 401.Li TELNET EOF 402(End Of File) 403sequence. 404.Tp Ic eor 405Sends the 406.Li TELNET EOR 407(End of Record) 408sequence. 409.Tp Ic escape 410Sends the current 411.Nm telnet 412escape character (initially \*(Lq^\*(Rq). 413.Tp Ic ga 414Sends the 415.Li TELNET GA 416(Go Ahead) 417sequence, which likely has no significance to the remote system. 418.Tp Ic getstatus 419If the remote side supports the 420.Li TELNET STATUS 421command, 422.Ic getstatus 423will send the subnegotiation to request that the server send 424its current option status. 425.Tp Ic ip 426Sends the 427.Li TELNET IP 428(Interrupt Process) sequence, which should cause the remote 429system to abort the currently running process. 430.Tp Ic nop 431Sends the 432.Li TELNET NOP 433(No OPeration) 434sequence. 435.Tp Ic susp 436Sends the 437.Li TELNET SUSP 438(SUSPend process) 439sequence. 440.Tp Ic synch 441Sends the 442.Li TELNET SYNCH 443sequence. 444This sequence causes the remote system to discard all previously typed 445(but not yet read) input. 446This sequence is sent as TCP urgent 447data (and may not work if the remote system is a 4.2 BSD system -- if 448it doesn't work, a lower case \*(Lqr\*(Rq may be echoed on the terminal). 449.Tp Ic \&? 450Prints out help information for the 451.Ic send 452command. 453.Tp 454.Tp Cx Ic set 455.Cx \&\ \& 456.Ar argument value 457.Cx 458.Tp Cx Ic unset 459.Cx \&\ \& 460.Ar argument value 461.Cx 462The 463.Ic set 464command will set any one of a number of 465.Nm telnet 466variables to a specific value or to TRUE. 467The special value 468.Ic off 469turns off the function associated with 470the variable, this is equivalent to using the 471.Ic unset 472command. 473The 474.Ic unset 475command will disable or set to FALSE any of the specified functions. 476The values of variables may be interrogated with the 477.Ic display 478command. 479The variables which may be set or unset, but not toggled, are 480listed here. In addition, any of the variables for the 481.Ic toggle 482command may be explicitly set or unset using 483the 484.Ic set 485and 486.Ic unset 487commands. 488.Tw Fl 489.Tp Ic echo 490This is the value (initially \*(Lq^E\*(Rq) which, when in 491\*(Lqline by line\*(Rq mode, toggles between doing local echoing 492of entered characters (for normal processing), and suppressing 493echoing of entered characters (for entering, say, a password). 494.Tp Ic eof 495If 496.Nm telnet 497is operating in 498.Li LINEMODE 499or \*(Lqold line by line\*(Rq mode, entering this character 500as the first character on a line will cause this character to be 501sent to the remote system. 502The initial value of the eof character is taken to be the terminal's 503.Ic eof 504character. 505.Tp Ic erase 506If 507.Nm telnet 508is in 509.Ic localchars 510mode (see 511.Ic toggle 512.Ic localchars 513below), 514.Sy and 515if 516.Nm telnet 517is operating in \*(Lqcharacter at a time\*(Rq mode, then when this 518character is typed, a 519.Li TELNET EC 520sequence (see 521.Ic send 522.Ic ec 523above) 524is sent to the remote system. 525The initial value for the erase character is taken to be 526the terminal's 527.Ic erase 528character. 529.Tp Ic escape 530This is the 531.Nm telnet 532escape character (initially \*(Lq^[\*(Rq) which causes entry 533into 534.Nm telnet 535command mode (when connected to a remote system). 536.Tp Ic flushoutput 537If 538.Nm telnet 539is in 540.Ic localchars 541mode (see 542.Ic toggle 543.Ic localchars 544below) 545and the 546.Ic flushoutput 547character is typed, a 548.Li TELNET AO 549sequence (see 550.Ic send 551.Ic ao 552above) 553is sent to the remote host. 554The initial value for the flush character is taken to be 555the terminal's 556.Ic flush 557character. 558.Tp Ic interrupt 559If 560.Nm telnet 561is in 562.Ic localchars 563mode (see 564.Ic toggle 565.Ic localchars 566below) 567and the 568.Ic interrupt 569character is typed, a 570.Li TELNET IP 571sequence (see 572.Ic send 573.Ic ip 574above) 575is sent to the remote host. 576The initial value for the interrupt character is taken to be 577the terminal's 578.Ic intr 579character. 580.Tp Ic kill 581If 582.Nm telnet 583is in 584.Ic localchars 585mode (see 586.Ic toggle 587.Ic localchars 588below), 589.Ic and 590if 591.Nm telnet 592is operating in \*(Lqcharacter at a time\*(Rq mode, then when this 593character is typed, a 594.Li TELNET EL 595sequence (see 596.Ic send 597.Ic el 598above) 599is sent to the remote system. 600The initial value for the kill character is taken to be 601the terminal's 602.Ic kill 603character. 604.Tp Ic lnext 605If 606.Nm telnet 607is operating in 608.Li LINEMODE 609or \*(Lqold line by line\*(Lq mode, then this character is taken to 610be the terminal's 611.Ic lnext 612character. 613The initial value for the lnext character is taken to be 614the terminal's 615.Ic lnext 616character. 617.Tp Ic quit 618If 619.Nm telnet 620is in 621.Ic localchars 622mode (see 623.Ic toggle 624.Ic localchars 625below) 626and the 627.Ic quit 628character is typed, a 629.Li TELNET BRK 630sequence (see 631.Ic send 632.Ic brk 633above) 634is sent to the remote host. 635The initial value for the quit character is taken to be 636the terminal's 637.Ic quit 638character. 639.Tp Ic reprint 640If 641.Nm telnet 642is operating in 643.Li LINEMODE 644or \*(Lqold line by line\*(Lq mode, then this character is taken to 645be the terminal's 646.Ic reprint 647character. 648The initial value for the reprint character is taken to be 649the terminal's 650.Ic reprint 651character. 652.Tp Ic start 653If the 654.Li TELNET TOGGLE-FLOW-CONTROL 655option has been enabled, 656then this character is taken to 657be the terminal's 658.Ic start 659character. 660The initial value for the kill character is taken to be 661the terminal's 662.Ic start 663character. 664.Tp Ic stop 665If the 666.Li TELNET TOGGLE-FLOW-CONTROL 667option has been enabled, 668then this character is taken to 669be the terminal's 670.Ic stop 671character. 672The initial value for the kill character is taken to be 673the terminal's 674.Ic stop 675character. 676.Tp Ic susp 677If 678.Nm telnet 679is in 680.Ic localchars 681mode, or 682.Li LINEMODE 683is enabled, and the 684.Ic suspend 685character is typed, a 686.Li TELNET SUSP 687sequence (see 688.Ic send 689.Ic susp 690above) 691is sent to the remote host. 692The initial value for the suspend character is taken to be 693the terminal's 694.Ic suspend 695character. 696.Tp Ic tracefile 697Thi is the file to which the output, caused by 698.Ic netdata 699or 700.Ic option 701tracing being TRUE, will be written. If it is set to 702.Dq Fl , 703then tracing information will be written to standard output (the default). 704.Tp Ic worderase 705If 706.Nm telnet 707is operating in 708.Li LINEMODE 709or \*(Lqold line by line\*(Lq mode, then this character is taken to 710be the terminal's 711.Ic worderase 712character. 713The initial value for the worderase character is taken to be 714the terminal's 715.Ic worderase 716character. 717.Tp Ic \&? 718Displays the legal 719.Ic set 720.Pq Ic unset 721commands. 722.Tp 723.Tp Cx Ic slc 724.Cx \&\ \& 725.Ar state 726.Cx 727The 728.Ic slc 729command (Set Local Characters) is used to set 730or change the state of the the special 731characters when the 732.Li TELNET LINEMODE 733option has 734been enabled. Special characters are characters that get 735mapped to 736.Li TELNET 737commands sequences (like 738.Ic ip 739or 740.Ic quit ) 741or line editing characters (like 742.Ic erase 743and 744.Ic kill ) . 745By default, the local special characters are exported. 746.Tw Fl 747.Tp Ic export 748Switch to the local defaults for the special characters. The 749local default characters are those of the local terminal at 750the time when 751.Nm telnet 752was started. 753.Tp Ic import 754Switch to the remote defaults for the special characters. 755The remote default characters are those of the remote system 756at the time when the 757.Li TELNET 758connection was established. 759.Tp Ic check 760Verify the current settings for the current special characters. 761The remote side is requested to send all the current special 762character settings, and if there are any discrepencies with 763the local side, the local side will switch to the remote value. 764.Tp Ic \&? 765Prints out help information for the 766.Ic slc 767command. 768.Tp 769.Tp Cx Ic environ 770.Cx \&\ \& 771.Ar arguments... 772.Cx 773The 774.Ic environ 775command is used to manipulate the 776the variables that my be sent through the 777.Li TELNET ENVIRON 778option. 779The initial set of variables is taken from the users 780environment, with only the 781.Ev DISPLAY 782and 783.Ev PRINTER 784variables being exported by default. 785The 786.Ev USER 787variable is also exported if the 788.Fl a 789or 790.Fl l 791options are used. 792.br 793Valid arguments for the \fBenviron\fP command are: 794.Tw Fl 795.Tp Cx Ic define 796.Cx \&\ \& 797.Ar variable value 798.Cx 799Define the variable 800.Ar variable 801to have a value of 802.Ar value. 803Any variables defined by this command are automatically exported. 804The 805.Ar value 806may be enclosed in single or double quotes so 807that tabs and spaces may be included. 808.Tp Cx Ic undefine 809.Cx \&\ \& 810.Ar variable 811.Cx 812Remove 813.Ar variable 814from the list of environment variables. 815.Tp Cx Ic export 816.Cx \&\ \& 817.Ar variable 818.Cx 819Mark the variable 820.Ar variable 821to be exported to the remote side. 822.Tp Cx Ic unexport 823.Cx \&\ \& 824.Ar variable 825.Cx 826Mark the variable 827.Ar variable 828to not be exported unless 829explicitly asked for by the remote side. 830.Tp Ic list 831List the current set of environment variables. 832Those marked with a \fB*\fR will be sent automatically, 833other variables will only be sent if explicitly requested. 834.Tp Ic \&? 835Prints out help information for the 836.Ic environ 837command. 838.Tp 839.Tp Cx Ic toggle 840.Cx \&\ \& 841.Ar arguments ... 842.Cx 843Toggle (between 844TRUE 845and 846FALSE) 847various flags that control how 848.Nm telnet 849responds to events. 850These flags may be set explicitly to TRUE or FALSE 851using the 852.Ic set 853and 854.Ic unset 855commands listed above. 856More than one argument may be specified. 857The state of these flags may be interrogated with the 858.Ic display 859command. 860Valid arguments are: 861.Tw Ar 862.Tp Ic autoflush 863If 864.Ic autoflush 865and 866.Ic localchars 867are both 868TRUE, 869then when the 870.Ic ao , 871or 872.Ic quit 873characters are recognized (and transformed into 874.Li TELNET 875sequences; see 876.Ic set 877above for details), 878.Nm telnet 879refuses to display any data on the user's terminal 880until the remote system acknowledges (via a 881.Li TELNET TIMING MARK 882option) 883that it has processed those 884.Li TELNET 885sequences. 886The initial value for this toggle is TRUE if the terminal user had not 887done an "stty noflsh", otherwise FALSE (see 888.Xr stty 1 ) . 889.Tp Ic autosynch 890If 891.Ic autosynch 892and 893.Ic localchars 894are both 895TRUE, 896then when either the 897.Ic intr 898or 899.Ic quit 900characters is typed (see 901.Ic set 902above for descriptions of the 903.Ic intr 904and 905.Ic quit 906characters), the resulting 907.Li TELNET 908sequence sent is followed by the 909.Li TELNET SYNCH 910sequence. 911This procedure 912.Ic should 913cause the remote system to begin throwing away all previously 914typed input until both of the 915.Li TELNET 916sequences have been read and acted upon. 917The initial value of this toggle is FALSE. 918.Tp Ic binary 919Enable or disable the 920.Li TELNET BINARY 921option on both input and output. 922.Tp Ic inbinary 923Enable or disable the 924.Li TELNET BINARY 925option on input. 926.Tp Ic outbinary 927Enable or disable the 928.Li TELNET BINARY 929option on output. 930.Tp Ic crlf 931If this is TRUE, then carriage returns will be sent as <CR><LF>. 932If this is FALSE, then carriage returns will be send as <CR><NUL>. 933The initial value for this toggle is FALSE. 934.Tp Ic crmod 935Toggle carriage return mode. 936When this mode is enabled, most carriage return characters received from 937the remote host will be mapped into a carriage return followed by 938a line feed. 939This mode does not affect those characters typed by the user, only 940those received from the remote host. 941This mode is not very useful unless the remote host 942only sends carriage return, but never line feed. 943The initial value for this toggle is FALSE. 944.Tp Ic debug 945Toggles socket level debugging (useful only to the 946.Ic super user ) . 947The initial value for this toggle is FALSE. 948.Tp Ic localchars 949If this is 950TRUE, 951then the 952.Ic flush , 953.Ic interrupt , 954.Ic quit , 955.Ic erase , 956and 957.Ic kill 958characters (see 959.Ic set 960above) are recognized locally, and transformed into (hopefully) appropriate 961.Li TELNET 962control sequences 963(respectively 964.Ic ao , 965.Ic ip , 966.Ic brk , 967.Ic ec , 968and 969.Ic el ; 970see 971.Ic send 972above). 973The initial value for this toggle is TRUE in \*(Lqold line by line\*(Rq mode, 974and FALSE in \*(Lqcharacter at a time\*(Rq mode. 975When the 976.Li LINEMODE 977option is enabled, the value of 978.Ic localchars 979is ignored, and assumed to always be TRUE. 980If 981.Li LINEMODE 982has ever been enabled, then 983.Ic quit 984is sent as 985.Ic abort , 986and 987.Ic eof and 988.B suspend 989are sent as 990.Ic eof and 991.Ic susp , 992see 993.Ic send 994above). 995.Tp Ic netdata 996Toggles the display of all network data (in hexadecimal format). 997The initial value for this toggle is FALSE. 998.Tp Ic options 999Toggles the display of some internal 1000.Nm telnet 1001protocol processing (having to do with 1002.Li TELNET 1003options). 1004The initial value for this toggle is FALSE. 1005.Tp Ic prettydump 1006When the 1007.Ic netdata 1008toggle is enabled, if 1009.Ic prettydump 1010is enabled the output from the 1011.Ic netdata 1012command will be formated in a more user readable format. 1013Spaces are put between each character in the output, and the 1014begining of any 1015.Li TELNET 1016escape sequence is preceeded by a '*' to aid in locating them. 1017.Tp Ic \&? 1018Displays the legal 1019.Ic toggle 1020commands. 1021.Tp 1022.Tp Ic z 1023Suspend 1024.Nm telnet . 1025This command only works when the user is using the 1026.Xr csh 1 . 1027.Tp Cx Ic \&! 1028.Cx \&\ \& 1029.Op Ar command 1030.Cx 1031Execute a single command in a subshell on the local 1032system. If 1033.Ic command 1034is ommitted, then an interactive 1035subshell is invoked. 1036.Tp Ic status 1037Show the current status of 1038.Nm telnet . 1039This includes the peer one is connected to, as well 1040as the current mode. 1041.Tp Cx Ic \&? 1042.Cx \&\ \& 1043.Op Ar command 1044.Cx 1045Get help. With no arguments, 1046.Nm telnet 1047prints a help summary. 1048If a command is specified, 1049.Nm telnet 1050will print the help information for just that command. 1051.Sh ENVIRONMENT 1052.Nm Telnet 1053uses at least the 1054.Ev HOME , 1055.Ev SHELL , 1056.Ev DISPLAY , 1057and 1058.Ev TERM 1059environent variables. 1060Other envirnoment variables may be propogated 1061to the other side via the 1062.Li TELNET ENVIRON 1063option. 1064.Sh FILES 1065.Dw ~/.telnetrc 1066.Di L 1067.Dp Pa ~/.telnetrc 1068user customized telnet startup values 1069.Dp 1070.Sh HISTORY 1071.Nm Telnet 1072appeared in 4.2 BSD. 1073.Sh NOTES 1074.Pp 1075On some remote systems, echo has to be turned off manually when in 1076\*(Lqold line by line\*(Rq mode. 1077.Pp 1078In \*(Lqold line by line\*(Rq mode or 1079.Li LINEMODE 1080the terminal's 1081.Ic eof 1082character is only recognized (and sent to the remote system) 1083when it is the first character on a line. 1084