1.\" Copyright (c) 1983, 1990 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.roff% 5.\" 6.\" @(#)telnet.1 6.16 (Berkeley) 07/27/91 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.Tn 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.Oo 23.Op Fl l Ar user 24.Ar host 25.Op port 26.Oc 27.Sh DESCRIPTION 28The 29.Nm telnet 30command 31is used to communicate with another host using the 32.Tn 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.Bl -tag -width indent 48.It Fl d 49Sets the initial value of the 50.Ic debug 51toggle to 52.Dv TRUE 53.It Fl a 54Attempt automatic login. 55Currently, this sends the user name via the 56.Ev USER 57variable 58of the 59.Ev ENVIRON 60option if supported by the remote system. 61The name used is that of the current user as returned by 62.Xr getlogin 2 63if it agrees with the current user ID, 64otherwise it is the name associated with the user ID. 65.It Fl n Ar tracefile 66Opens 67.Ar tracefile 68for recording trace information. 69See the 70.Ic set tracefile 71command below. 72.It Fl l Ar user 73When connecting to the remote system, if the remote system 74understands the 75.Ev ENVIRON 76option, 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.It Fl e Ar escape char 86Sets the initial 87.Nm 88.Nm telnet 89escape character to 90.Ar escape char. 91If 92.Ar escape char 93is ommitted, then 94there will be no escape character. 95.It Ar host 96Indicates the official name, an alias, or the Internet address 97of a remote host. 98.It Ar port 99Indicates a port number (address of an application). If a number is 100not specified, the default 101.Nm telnet 102port is used. 103.El 104.Pp 105Once a connection has been opened, 106.Nm telnet 107will attempt to enable the 108.Dv TELNET LINEMODE 109option. 110If this fails, then 111.Nm telnet 112will revert to one of two input modes: 113either \*(Lqcharacter at a time\*(Rq 114or \*(Lqold line by line\*(Rq 115depending on what the remote system supports. 116.Pp 117When 118.Dv LINEMODE 119is enabled, character processing is done on the 120local system, under the control of the remote system. When input 121editing or character echoing is to be disabled, the remote system 122will relay that information. The remote system will also relay 123changes to any special characters that happen on the remote 124system, so that they can take effect on the local system. 125.Pp 126In \*(Lqcharacter at a time\*(Rq mode, most 127text typed is immediately sent to the remote host for processing. 128.Pp 129In \*(Lqold line by line\*(Rq mode, all text is echoed locally, 130and (normally) only completed lines are sent to the remote host. 131The \*(Lqlocal echo character\*(Rq (initially \*(Lq^E\*(Rq) may be used 132to turn off and on the local echo 133(this would mostly be used to enter passwords 134without the password being echoed). 135.Pp 136If the 137.Dv LINEMODE 138option is enabled, or if the 139.Ic localchars 140toggle is 141.Dv TRUE 142(the default for \*(Lqold line by line\*(Lq; see below), 143the user's 144.Ic quit , 145.Ic intr , 146and 147.Ic flush 148characters are trapped locally, and sent as 149.Tn TELNET 150protocol sequences to the remote side. 151If 152.Dv LINEMODE 153has ever been enabled, then the user's 154.Ic susp 155and 156.Ic eof 157are also sent as 158.Tn TELNET 159protocol sequences, 160and 161.Ic quit 162is sent as a 163.Dv TELNET ABORT 164instead of 165.Dv BREAK 166There are options (see 167.Ic toggle 168.Ic autoflush 169and 170.Ic toggle 171.Ic autosynch 172below) 173which cause this action to flush subsequent output to the terminal 174(until the remote host acknowledges the 175.Tn TELNET 176sequence) and flush previous terminal input 177(in the case of 178.Ic quit 179and 180.Ic intr ) . 181.Pp 182While connected to a remote host, 183.Nm telnet 184command mode may be entered by typing the 185.Nm telnet 186\*(Lqescape character\*(Rq (initially \*(Lq^]\*(Rq). 187When in command mode, the normal terminal editing conventions are available. 188.Pp 189The following 190.Nm telnet 191commands are available. 192Only enough of each command to uniquely identify it need be typed 193(this is also true for arguments to the 194.Ic mode , 195.Ic set , 196.Ic toggle , 197.Ic unset , 198.Ic slc , 199.Ic environ , 200and 201.Ic display 202commands). 203.Pp 204.Bl -tag -width "mode type" 205.It Ic close 206Close a 207.Tn TELNET 208session and return to command mode. 209.It Ic display Ar argument ... 210Displays all, or some, of the 211.Ic set 212and 213.Ic toggle 214values (see below). 215.It Ic mode Ar type 216.Ar Type 217is one of several options, depending on the state of the 218.Tn TELNET 219session. 220The remote host is asked for permission to go into the requested mode. 221If the remote host is capable of entering that mode, the requested 222mode will be entered. 223.Bl -tag -width Ar 224.It Ic character 225Disable the 226.Dv TELNET LINEMODE 227option, or, if the remote side does not understand the 228.Dv LINEMODE 229option, then enter \*(Lqcharacter at a time\*(Lq mode. 230.It Ic line 231Enable the 232.Dv TELNET LINEMODE 233option, or, if the remote side does not understand the 234.Dv LINEMODE 235option, then attempt to enter \*(Lqold-line-by-line\*(Lq mode. 236.It Ic isig Pq Ic \-isig 237Attempt to enable (disable) the 238.Dv TRAPSIG 239mode of the 240.Dv LINEMODE 241option. 242This requires that the 243.Dv LINEMODE 244option be enabled. 245.It Ic edit Pq Ic \-edit 246Attempt to enable (disable) the 247.Dv EDIT 248mode of the 249.Dv LINEMODE 250option. 251This requires that the 252.Dv LINEMODE 253option be enabled. 254.It Ic softtabs Pq Ic \-softtabs 255Attempt to enable (disable) the 256.Dv SOFT_TAB 257mode of the 258.Dv LINEMODE 259option. 260This requires that the 261.Dv LINEMODE 262option be enabled. 263.It Ic litecho Pq Ic \-litecho 264Attempt to enable (disable) the 265.Dv LIT_ECHO 266mode of the 267.Dv LINEMODE 268option. 269This requires that the 270.Dv LINEMODE 271option be enabled. 272.It Ic \&? 273Prints out help information for the 274.Ic mode 275command. 276.El 277.It Xo 278.Ic open Ar host 279.Oo Op Fl l 280.Ar user 281.Oc Ns Oo Fl 282.Ar port Oc 283.Xc 284Open a connection to the named host. 285If no port number 286is specified, 287.Nm telnet 288will attempt to contact a 289.Tn TELNET 290server at the default port. 291The host specification may be either a host name (see 292.Xr hosts 5 ) 293or an Internet address specified in the \*(Lqdot notation\*(Rq (see 294.Xr inet 3 ) . 295The 296.Op Fl l 297option may be used to specify the user name 298to be passed to the remote system via the 299.Ev ENVIRON 300option. 301When connecting to a non-standard port, 302.Nm telnet 303omits any automatic initiation of 304.Tn TELNET 305options. When the port number is preceeded by a minus sign, 306the inital option negotiation is done. 307After establishing a connection, the file 308.Pa \&.telnetrc 309in the 310users home directory is opened. Lines begining with a # are 311comment lines. Blank lines are ignored. Lines that begin 312without whitespace are the start of a machine entry. The 313first thing on the line is the name of the machine that is 314being connected to. The rest of the line, and successive 315lines that begin with whitespace are assumed to be 316.Nm telnet 317commands and are processed as if they had been typed 318in manually to the 319.Nm telnet 320command prompt. 321.It Ic quit 322Close any open 323.Tn TELNET 324session and exit 325.Nm telnet . 326An end of file (in command mode) will also close a session and exit. 327.It Ic send Ar arguments 328Sends one or more special character sequences to the remote host. 329The following are the arguments which may be specified 330(more than one argument may be specified at a time): 331.Pp 332.Bl -tag -width escape 333.It Ic abort 334Sends the 335.Dv TELNET ABORT 336(Abort 337processes) 338sequence. 339.It Ic ao 340Sends the 341.Dv TELNET AO 342(Abort Output) sequence, which should cause the remote system to flush 343all output 344.Em from 345the remote system 346.Em to 347the user's terminal. 348.It Ic ayt 349Sends the 350.Dv TELNET AYT 351(Are You There) 352sequence, to which the remote system may or may not choose to respond. 353.It Ic brk 354Sends the 355.Dv TELNET BRK 356(Break) sequence, which may have significance to the remote 357system. 358.It Ic ec 359Sends the 360.Dv TELNET EC 361(Erase Character) 362sequence, which should cause the remote system to erase the last character 363entered. 364.It Ic el 365Sends the 366.Dv TELNET EL 367(Erase Line) 368sequence, which should cause the remote system to erase the line currently 369being entered. 370.It Ic eof 371Sends the 372.Dv TELNET EOF 373(End Of File) 374sequence. 375.It Ic eor 376Sends the 377.Dv TELNET EOR 378(End of Record) 379sequence. 380.It Ic escape 381Sends the current 382.Nm telnet 383escape character (initially \*(Lq^\*(Rq). 384.It Ic ga 385Sends the 386.Dv TELNET GA 387(Go Ahead) 388sequence, which likely has no significance to the remote system. 389.It Ic getstatus 390If the remote side supports the 391.Dv TELNET STATUS 392command, 393.Ic getstatus 394will send the subnegotiation to request that the server send 395its current option status. 396.It Ic ip 397Sends the 398.Dv TELNET IP 399(Interrupt Process) sequence, which should cause the remote 400system to abort the currently running process. 401.It Ic nop 402Sends the 403.Dv TELNET NOP 404(No OPeration) 405sequence. 406.It Ic susp 407Sends the 408.Dv TELNET SUSP 409(SUSPend process) 410sequence. 411.It Ic synch 412Sends the 413.Dv TELNET SYNCH 414sequence. 415This sequence causes the remote system to discard all previously typed 416(but not yet read) input. 417This sequence is sent as 418.Tn TCP 419urgent 420data (and may not work if the remote system is a 421.Bx 4.2 422system -- if 423it doesn't work, a lower case \*(Lqr\*(Rq may be echoed on the terminal). 424.It Ic \&? 425Prints out help information for the 426.Ic send 427command. 428.El 429.It Ic set Ar argument value 430.It Ic unset Ar argument value 431The 432.Ic set 433command will set any one of a number of 434.Nm telnet 435variables to a specific value or to 436.Dv TRUE . 437The special value 438.Ic off 439turns off the function associated with 440the variable, this is equivalent to using the 441.Ic unset 442command. 443The 444.Ic unset 445command will disable or set to 446.Dv FALSE 447any of the specified functions. 448The values of variables may be interrogated with the 449.Ic display 450command. 451The variables which may be set or unset, but not toggled, are 452listed here. In addition, any of the variables for the 453.Ic toggle 454command may be explicitly set or unset using 455the 456.Ic set 457and 458.Ic unset 459commands. 460.Bl -tag -width escape 461.It Ic echo 462This is the value (initially \*(Lq^E\*(Rq) which, when in 463\*(Lqline by line\*(Rq mode, toggles between doing local echoing 464of entered characters (for normal processing), and suppressing 465echoing of entered characters (for entering, say, a password). 466.It Ic eof 467If 468.Nm telnet 469is operating in 470.Dv LINEMODE 471or \*(Lqold line by line\*(Rq mode, entering this character 472as the first character on a line will cause this character to be 473sent to the remote system. 474The initial value of the eof character is taken to be the terminal's 475.Ic eof 476character. 477.It Ic erase 478If 479.Nm telnet 480is in 481.Ic localchars 482mode (see 483.Ic toggle 484.Ic localchars 485below), 486.Sy and 487if 488.Nm telnet 489is operating in \*(Lqcharacter at a time\*(Rq mode, then when this 490character is typed, a 491.Dv TELNET EC 492sequence (see 493.Ic send 494.Ic ec 495above) 496is sent to the remote system. 497The initial value for the erase character is taken to be 498the terminal's 499.Ic erase 500character. 501.It Ic escape 502This is the 503.Nm telnet 504escape character (initially \*(Lq^[\*(Rq) which causes entry 505into 506.Nm telnet 507command mode (when connected to a remote system). 508.It Ic flushoutput 509If 510.Nm telnet 511is in 512.Ic localchars 513mode (see 514.Ic toggle 515.Ic localchars 516below) 517and the 518.Ic flushoutput 519character is typed, a 520.Dv TELNET AO 521sequence (see 522.Ic send 523.Ic ao 524above) 525is sent to the remote host. 526The initial value for the flush character is taken to be 527the terminal's 528.Ic flush 529character. 530.It Ic interrupt 531If 532.Nm telnet 533is in 534.Ic localchars 535mode (see 536.Ic toggle 537.Ic localchars 538below) 539and the 540.Ic interrupt 541character is typed, a 542.Dv TELNET IP 543sequence (see 544.Ic send 545.Ic ip 546above) 547is sent to the remote host. 548The initial value for the interrupt character is taken to be 549the terminal's 550.Ic intr 551character. 552.It Ic kill 553If 554.Nm telnet 555is in 556.Ic localchars 557mode (see 558.Ic toggle 559.Ic localchars 560below), 561.Ic and 562if 563.Nm telnet 564is operating in \*(Lqcharacter at a time\*(Rq mode, then when this 565character is typed, a 566.Dv TELNET EL 567sequence (see 568.Ic send 569.Ic el 570above) 571is sent to the remote system. 572The initial value for the kill character is taken to be 573the terminal's 574.Ic kill 575character. 576.It Ic lnext 577If 578.Nm telnet 579is operating in 580.Dv LINEMODE 581or \*(Lqold line by line\*(Lq mode, then this character is taken to 582be the terminal's 583.Ic lnext 584character. 585The initial value for the lnext character is taken to be 586the terminal's 587.Ic lnext 588character. 589.It Ic quit 590If 591.Nm telnet 592is in 593.Ic localchars 594mode (see 595.Ic toggle 596.Ic localchars 597below) 598and the 599.Ic quit 600character is typed, a 601.Dv TELNET BRK 602sequence (see 603.Ic send 604.Ic brk 605above) 606is sent to the remote host. 607The initial value for the quit character is taken to be 608the terminal's 609.Ic quit 610character. 611.It Ic reprint 612If 613.Nm telnet 614is operating in 615.Dv LINEMODE 616or \*(Lqold line by line\*(Lq mode, then this character is taken to 617be the terminal's 618.Ic reprint 619character. 620The initial value for the reprint character is taken to be 621the terminal's 622.Ic reprint 623character. 624.It Ic start 625If the 626.Dv TELNET TOGGLE-FLOW-CONTROL 627option has been enabled, 628then this character is taken to 629be the terminal's 630.Ic start 631character. 632The initial value for the kill character is taken to be 633the terminal's 634.Ic start 635character. 636.It Ic stop 637If the 638.Dv TELNET TOGGLE-FLOW-CONTROL 639option has been enabled, 640then this character is taken to 641be the terminal's 642.Ic stop 643character. 644The initial value for the kill character is taken to be 645the terminal's 646.Ic stop 647character. 648.It Ic susp 649If 650.Nm telnet 651is in 652.Ic localchars 653mode, or 654.Dv LINEMODE 655is enabled, and the 656.Ic suspend 657character is typed, a 658.Dv TELNET SUSP 659sequence (see 660.Ic send 661.Ic susp 662above) 663is sent to the remote host. 664The initial value for the suspend character is taken to be 665the terminal's 666.Ic suspend 667character. 668.It Ic tracefile 669Thi is the file to which the output, caused by 670.Ic netdata 671or 672.Ic option 673tracing being 674.Dv TRUE , 675will be written. If it is set to 676.Dq Fl , 677then tracing information will be written to standard output (the default). 678.It Ic worderase 679If 680.Nm telnet 681is operating in 682.Dv LINEMODE 683or \*(Lqold line by line\*(Lq mode, then this character is taken to 684be the terminal's 685.Ic worderase 686character. 687The initial value for the worderase character is taken to be 688the terminal's 689.Ic worderase 690character. 691.It Ic \&? 692Displays the legal 693.Ic set 694.Pq Ic unset 695commands. 696.El 697.It Ic slc Ar state 698The 699.Ic slc 700command (Set Local Characters) is used to set 701or change the state of the the special 702characters when the 703.Dv TELNET LINEMODE 704option has 705been enabled. Special characters are characters that get 706mapped to 707.Tn TELNET 708commands sequences (like 709.Ic ip 710or 711.Ic quit ) 712or line editing characters (like 713.Ic erase 714and 715.Ic kill ) . 716By default, the local special characters are exported. 717.Bl -tag -width Fl 718.It Ic export 719Switch to the local defaults for the special characters. The 720local default characters are those of the local terminal at 721the time when 722.Nm telnet 723was started. 724.It Ic import 725Switch to the remote defaults for the special characters. 726The remote default characters are those of the remote system 727at the time when the 728.Tn TELNET 729connection was established. 730.It Ic check 731Verify the current settings for the current special characters. 732The remote side is requested to send all the current special 733character settings, and if there are any discrepencies with 734the local side, the local side will switch to the remote value. 735.It Ic \&? 736Prints out help information for the 737.Ic slc 738command. 739.El 740.It Ic environ Ar arguments... 741The 742.Ic environ 743command is used to manipulate the 744the variables that my be sent through the 745.Dv TELNET ENVIRON 746option. 747The initial set of variables is taken from the users 748environment, with only the 749.Ev DISPLAY 750and 751.Ev PRINTER 752variables being exported by default. 753The 754.Ev USER 755variable is also exported if the 756.Fl a 757or 758.Fl l 759options are used. 760.br 761Valid arguments for the 762.Ic environ 763command are: 764.Bl -tag -width Fl 765.It Ic define Ar variable value 766Define the variable 767.Ar variable 768to have a value of 769.Ar value. 770Any variables defined by this command are automatically exported. 771The 772.Ar value 773may be enclosed in single or double quotes so 774that tabs and spaces may be included. 775.It Ic undefine Ar variable 776Remove 777.Ar variable 778from the list of environment variables. 779.It Ic export Ar variable 780Mark the variable 781.Ar variable 782to be exported to the remote side. 783.It Ic unexport Ar variable 784Mark the variable 785.Ar variable 786to not be exported unless 787explicitly asked for by the remote side. 788.It Ic list 789List the current set of environment variables. 790Those marked with a 791.Cm * 792will be sent automatically, 793other variables will only be sent if explicitly requested. 794.It Ic \&? 795Prints out help information for the 796.Ic environ 797command. 798.El 799.It Ic toggle Ar arguments ... 800Toggle (between 801.Dv TRUE 802and 803.Dv FALSE ) 804various flags that control how 805.Nm telnet 806responds to events. 807These flags may be set explicitly to 808.Dv TRUE 809or 810.Dv FALSE 811using the 812.Ic set 813and 814.Ic unset 815commands listed above. 816More than one argument may be specified. 817The state of these flags may be interrogated with the 818.Ic display 819command. 820Valid arguments are: 821.Bl -tag -width Ar 822.It Ic autoflush 823If 824.Ic autoflush 825and 826.Ic localchars 827are both 828.Dv TRUE , 829then when the 830.Ic ao , 831or 832.Ic quit 833characters are recognized (and transformed into 834.Tn TELNET 835sequences; see 836.Ic set 837above for details), 838.Nm telnet 839refuses to display any data on the user's terminal 840until the remote system acknowledges (via a 841.Dv TELNET TIMING MARK 842option) 843that it has processed those 844.Tn TELNET 845sequences. 846The initial value for this toggle is 847.Dv TRUE 848if the terminal user had not 849done an "stty noflsh", otherwise 850.Dv FALSE 851(see 852.Xr stty 1 ) . 853.It Ic autosynch 854If 855.Ic autosynch 856and 857.Ic localchars 858are both 859.Dv TRUE , 860then when either the 861.Ic intr 862or 863.Ic quit 864characters is typed (see 865.Ic set 866above for descriptions of the 867.Ic intr 868and 869.Ic quit 870characters), the resulting 871.Tn TELNET 872sequence sent is followed by the 873.Dv TELNET SYNCH 874sequence. 875This procedure 876.Ic should 877cause the remote system to begin throwing away all previously 878typed input until both of the 879.Tn TELNET 880sequences have been read and acted upon. 881The initial value of this toggle is 882.Dv FALSE . 883.It Ic binary 884Enable or disable the 885.Dv TELNET BINARY 886option on both input and output. 887.It Ic inbinary 888Enable or disable the 889.Dv TELNET BINARY 890option on input. 891.It Ic outbinary 892Enable or disable the 893.Dv TELNET BINARY 894option on output. 895.It Ic crlf 896If this is 897.Dv TRUE , 898then carriage returns will be sent as 899.Li <CR><LF> . 900If this is 901.Dv FALSE , 902then carriage returns will be send as 903.Li <CR><NUL> . 904The initial value for this toggle is 905.Dv FALSE . 906.It Ic crmod 907Toggle carriage return mode. 908When this mode is enabled, most carriage return characters received from 909the remote host will be mapped into a carriage return followed by 910a line feed. 911This mode does not affect those characters typed by the user, only 912those received from the remote host. 913This mode is not very useful unless the remote host 914only sends carriage return, but never line feed. 915The initial value for this toggle is 916.Dv FALSE . 917.It Ic debug 918Toggles socket level debugging (useful only to the 919.Ic super user ) . 920The initial value for this toggle is 921.Dv FALSE . 922.It Ic localchars 923If this is 924.Dv TRUE , 925then the 926.Ic flush , 927.Ic interrupt , 928.Ic quit , 929.Ic erase , 930and 931.Ic kill 932characters (see 933.Ic set 934above) are recognized locally, and transformed into (hopefully) appropriate 935.Tn TELNET 936control sequences 937(respectively 938.Ic ao , 939.Ic ip , 940.Ic brk , 941.Ic ec , 942and 943.Ic el ; 944see 945.Ic send 946above). 947The initial value for this toggle is 948.Dv TRUE 949in \*(Lqold line by line\*(Rq mode, 950and 951.Dv FALSE 952in \*(Lqcharacter at a time\*(Rq mode. 953When the 954.Dv LINEMODE 955option is enabled, the value of 956.Ic localchars 957is ignored, and assumed to always be 958.Dv TRUE . 959If 960.Dv LINEMODE 961has ever been enabled, then 962.Ic quit 963is sent as 964.Ic abort , 965and 966.Ic eof and 967.B suspend 968are sent as 969.Ic eof and 970.Ic susp , 971see 972.Ic send 973above). 974.It Ic netdata 975Toggles the display of all network data (in hexadecimal format). 976The initial value for this toggle is 977.Dv FALSE . 978.It Ic options 979Toggles the display of some internal 980.Nm telnet 981protocol processing (having to do with 982.Tn TELNET 983options). 984The initial value for this toggle is 985.Dv FALSE . 986.It Ic prettydump 987When the 988.Ic netdata 989toggle is enabled, if 990.Ic prettydump 991is enabled the output from the 992.Ic netdata 993command will be formated in a more user readable format. 994Spaces are put between each character in the output, and the 995begining of any 996.Tn TELNET 997escape sequence is preceeded by a '*' to aid in locating them. 998.It Ic \&? 999Displays the legal 1000.Ic toggle 1001commands. 1002.El 1003.It Ic z 1004Suspend 1005.Nm telnet . 1006This command only works when the user is using the 1007.Xr csh 1 . 1008.It Ic \&! Op Ar command 1009Execute a single command in a subshell on the local 1010system. If 1011.Ic command 1012is ommitted, then an interactive 1013subshell is invoked. 1014.It Ic status 1015Show the current status of 1016.Nm telnet . 1017This includes the peer one is connected to, as well 1018as the current mode. 1019.It Ic \&? Op Ar command 1020Get help. With no arguments, 1021.Nm telnet 1022prints a help summary. 1023If a command is specified, 1024.Nm telnet 1025will print the help information for just that command. 1026.El 1027.Sh ENVIRONMENT 1028.Nm Telnet 1029uses at least the 1030.Ev HOME , 1031.Ev SHELL , 1032.Ev DISPLAY , 1033and 1034.Ev TERM 1035environent variables. 1036Other envirnoment variables may be propogated 1037to the other side via the 1038.Dv TELNET ENVIRON 1039option. 1040.Sh FILES 1041.Bl -tag -width ~/.telnetrc -compact 1042.It Pa ~/.telnetrc 1043user customized telnet startup values 1044.El 1045.Sh HISTORY 1046The 1047.Nm Telnet 1048command appeared in 1049.Bx 4.2 . 1050.Sh NOTES 1051.Pp 1052On some remote systems, echo has to be turned off manually when in 1053\*(Lqold line by line\*(Rq mode. 1054.Pp 1055In \*(Lqold line by line\*(Rq mode or 1056.Dv LINEMODE 1057the terminal's 1058.Ic eof 1059character is only recognized (and sent to the remote system) 1060when it is the first character on a line. 1061