9term.1 (10587B)
1 .TH 9TERM 1 2 .SH NAME 3 9term \- terminal windows 4 .SH SYNOPSIS 5 .B 9term 6 [ 7 .B -asc 8 ] 9 [ 10 .B -f 11 .I font 12 ] 13 [ 14 .I cmd 15 \&... 16 ] 17 .SH DESCRIPTION 18 .I 9term 19 is a terminal window program for the X Window System, 20 providing an interface similar to that used on Plan 9. 21 .SS Command 22 The 23 .I 9term 24 command starts a new window. 25 .PP 26 The 27 .B -a 28 flag causes button 2 to send the selection immediately, like acme. 29 Otherwise button 2 brings up a menu, described below. 30 .PP 31 The 32 .B -s 33 option has no effect. It formerly set the scrolling mode, 34 and is recognized to avoid breaking scripts that create new windows. 35 See below for a description of scrolling behavior. 36 .PP 37 The 38 .B -c 39 option starts the window in forced cooked mode, 40 described below. 41 .PP 42 The 43 .I font 44 argument to 45 .B -f 46 names a font used to display text, both in 47 .IR 9term 's 48 menus 49 and as a default for any programs running in its windows; it also 50 establishes the 51 environment variable 52 .BR $font . 53 If 54 .B -f 55 is not given, 56 .I 9term 57 uses the imported value of 58 .B $font 59 if set; otherwise it uses the graphics system default. 60 (See 61 .MR font (7) 62 for a full discussion of font syntaxes.) 63 .PP 64 .I 9term 65 runs the given command in the window, or 66 .B $SHELL 67 if no command is given. 68 .SS Text windows 69 Characters typed on the keyboard 70 collect in the window to form 71 a long, continuous document. 72 .PP 73 There is always some 74 .I selected 75 .IR text , 76 a contiguous string marked on the screen by reversing its color. 77 If the selected text is a null string, it is indicated by a hairline cursor 78 between two characters. 79 The selected text 80 may be edited by mousing and typing. 81 Text is selected by pointing and clicking button 1 82 to make a null-string selection, or by pointing, 83 then sweeping with button 1 pressed. 84 Text may also be selected by double-clicking: 85 just inside a matched delimiter-pair 86 with one of 87 .B {[(<`'" 88 on the left and 89 .B }])>`'" 90 on the right, it selects all text within 91 the pair; at the beginning 92 or end of a line, it selects the line; within or at the edge of an alphanumeric word, 93 it selects the word. 94 .PP 95 Characters typed on the keyboard replace the selected text; 96 if this text is not empty, it is placed in a 97 .I snarf buffer 98 common to all windows but distinct from that of 99 .MR sam (1) . 100 .PP 101 Programs access the text in the window at a single point 102 maintained automatically by 103 .IR 9term . 104 The 105 .I output point 106 is the location in the text where the next character written by 107 a program to the terminal 108 will appear; afterwards, the output point is the null string 109 beyond the new character. 110 The output point is also the location in the text of the next character 111 that will be read (directly from the text in the window, 112 not from an intervening buffer) 113 by a program. 114 Since Unix does not make it possible to know when a program 115 is reading the terminal, lines are sent as they are completed 116 (when the user types a newline character). 117 .PP 118 In general there is text in the window after the output point, 119 usually placed there by typing but occasionally by the editing 120 operations described below. 121 A pending read of the terminal 122 will block until the text after the output point contains 123 a newline, whereupon the read may 124 acquire the text, up to and including the newline. 125 After the read, as described above, the output point will be at 126 the beginning of the next line of text. 127 In normal circumstances, therefore, typed text is delivered 128 to programs a line at a time. 129 Changes made by typing or editing before the text is read will not 130 be seen by the program reading it. 131 Because of the Unix issues mentioned above, a line of text is only editable 132 until it is completed with a newline character, or when hold mode 133 (see below) is enabled. 134 .PP 135 Even when there are newlines in the output text, 136 .I 9term 137 will not honor reads if the window is in 138 .I hold 139 .IR mode , 140 which is indicated by a white cursor and blue text and border. 141 The ESC character toggles hold mode. 142 Some programs 143 automatically turn on hold mode to simplify the editing of multi-line text; 144 type ESC when done to allow 145 .I mail 146 to read the text. 147 .PP 148 An EOT character (control-D) behaves exactly like newline except 149 that it is not delivered to a program when read. 150 Thus on an empty line an EOT serves to deliver an end-of-file indication: 151 the read will return zero characters. 152 .\" Like newlines, unread EOTs may be successfully edited out of the text. 153 The BS character (control-H) erases the character before the selected text. 154 The ETB character (control-W) erases any nonalphanumeric characters, then 155 the alphanumeric word just before the selected text. 156 `Alphanumeric' here means non-blanks and non-punctuation. 157 The NAK character (control-U) erases the text after the output point, 158 and not yet read by a program, but not more than one line. 159 All these characters are typed on the keyboard and hence replace 160 the selected text; for example, typing a BS with a word selected 161 places the word in the snarf buffer, removes it from the screen, 162 and erases the character before the word. 163 .PP 164 An ACK character (control-F) or Insert character triggers file name completion 165 for the preceding string (see 166 .MR complete (3) ). 167 .PP 168 Text may be moved vertically within the window. 169 A scroll bar on the left of the window shows in its clear portion what fragment of the 170 total output text is visible on the screen, and in its grey part what 171 is above or below view; 172 it measures characters, not lines. 173 Mousing inside the scroll bar moves text: 174 clicking button 1 with the mouse pointing inside the scroll bar 175 brings the line at the top of the 176 window to the cursor's vertical location; 177 button 3 takes the line at the cursor to the top of the window; 178 button 2, treating the scroll bar as a ruler, jumps to the indicated portion 179 of the stored text. 180 Holding a button pressed in the scroll bar will cause the text 181 to scroll continuously until the button is released. 182 .PP 183 Typing down-arrow scrolls forward 184 one third of a window, and up-arrow scrolls back. 185 Typing page-down scrolls forward 186 two thirds of a window, and page-up scrolls back. 187 Typing Home scrolls to the top of the window; 188 typing End scrolls to the end. 189 .PP 190 The DEL character sends an 191 .L interrupt 192 note to all processes in the window's process group. 193 Unlike the other characters, the DEL and arrow 194 keys do not affect the selected text. 195 The left (right) arrow key moves the selection to one character 196 before (after) the current selection. 197 .PP 198 .I 9term 199 relies on the kernel's terminal processing to handle 200 EOT, so the terminal must be set up with EOT 201 as the ``eof'' character. 202 .I 9term 203 runs 204 .MR stty (1) 205 to establish this when the terminal is created. 206 .PP 207 .I 9term 208 always treats the DEL keystroke as an interrupt request. 209 In response it sends the terminal's current interrupt character 210 (which need not be DEL). 211 .PP 212 Written output to a window is appended to the end of the window. 213 The window scrolls to display the new output only if the 214 end of the window was visible before the write. 215 .PP 216 .I 9term 217 changes behavior according to 218 the terminal settings of the running programs. 219 Most programs run with echo enabled. 220 In this mode, 221 .I 9term 222 displays and allows editing of the input. 223 Some programs, typically those reading passwords, 224 run with echo disabled. 225 In this mode, 226 .I 9term 227 passes keystrokes through directly, without 228 echoing them or buffering until a newline character. 229 These heuristics work well in many cases, but there 230 are a few common ones where they fall short. 231 First, programs using the GNU readline library typically 232 disable terminal echo and perform echoing themselves. 233 The most common example is the shell 234 .MR bash (1) . 235 Disabling the use of readline with 236 .RB `` "set +o emacs" '' 237 .RI [ sic ] 238 usually restores the desired behavior. 239 Second, remote terminal programs such as 240 .MR ssh (1) 241 typically run with echo disabled, relying on the 242 remote system to echo characters as desired. 243 Plan 9's 244 .I ssh 245 has a 246 .B -C 247 flag to disable this, leaving the terminal in ``cooked'' mode. 248 For similar situations on Unix, 249 .IR 9term 's 250 button 2 menu has an entry to toggle the forced use of 251 cooked mode, despite the terminal settings. 252 In such cases, it is useful to run 253 .RB `` "stty -echo" '' 254 on the remote system to avoid seeing your input twice. 255 .PP 256 Editing operations are selected from a menu on button 2. 257 The 258 .B cut 259 operation deletes the selected text 260 from the screen and puts it in the snarf buffer; 261 .B snarf 262 copies the selected text to the buffer without deleting it; 263 .B paste 264 replaces the selected text with the contents of the buffer; 265 and 266 .B send 267 copies the snarf buffer to just after the output point, adding a final newline 268 if missing. 269 .B Paste 270 will sometimes and 271 .B send 272 will always place text after the output point; the text so placed 273 will behave exactly as described above. Therefore when pasting 274 text containing newlines after the output point, it may be prudent 275 to turn on hold mode first. 276 .PP 277 The 278 .B plumb 279 menu item sends the contents of the selection (not the snarf buffer) to the 280 .I plumber 281 (see 282 .MR plumb (1) ). 283 If the selection is empty, it sends the white-space-delimited text 284 containing the selection (typing cursor). 285 A typical use of this feature is to tell the editor to find the source of an error 286 by plumbing the file and line information in a compiler's diagnostic. 287 .PP 288 The 289 .B look 290 menu item searches forward for the contents of the selection within 291 the window. If a match is found, it becomes the new selection and the 292 window scrolls to display it. The search wraps around to the beginning 293 of the windows if the end of the window is reached. 294 .PP 295 For systems without a three-button mouse, the keyboard modifier 296 keys can be used to modify the effect of the main mouse button. 297 On Unix systems, the Control key changes the main button to button 2, 298 and the Alt key changes it to button 3. 299 On Mac systems, the Option key changes the main button to button 2, 300 and the Command key changes it to button 3. 301 Also on Mac systems, the usual keyboard shortcuts 302 Command-C, -V, and -X invoke 303 copy, paste, and cut, 304 as in other programs. 305 .PP 306 Each 307 .I 9term 308 listens for connections on a Unix socket. 309 When a client connects, the 310 .I 9term 311 writes the window contents to the client and then hangs up. 312 .I 9term 313 installs the name of this socket in the environment as 314 .B $text9term 315 before running 316 .IR cmd . 317 .SH SOURCE 318 .B \*9/src/cmd/9term 319 .SH BUGS 320 There should be a program to toggle the current window's hold mode. 321 .PP 322 Not a 323 .IR 9term 324 bug: 325 when running 326 .MR bash (1) 327 in 328 .RB `` "set +o emacs" '' 329 mode, its handling of interrupts is broken. 330 In response to DEL, 331 .I bash 332 processes the interrupt but then silently discards the next 333 character typed. 334 .PP 335 Unix makes everything harder. 336 .SH SEE ALSO 337 .MR wintext (1)