FAQ (8634B)
1 ## Why does st not handle utmp entries? 2 3 Use the excellent tool of [utmp](https://git.suckless.org/utmp/) for this task. 4 5 ## Some _random program_ complains that st is unknown/not recognised/unsupported/whatever! 6 7 It means that st doesn’t have any terminfo entry on your system. Chances are 8 you did not `make install`. If you just want to test it without installing it, 9 you can manually run `tic -sx st.info`. 10 11 ## Nothing works, and nothing is said about an unknown terminal! 12 13 * Some programs just assume they’re running in xterm i.e. they don’t rely on 14 terminfo. What you see is the current state of the “xterm compliance”. 15 * Some programs don’t complain about the lacking st description and default to 16 another terminal. In that case see the question about terminfo. 17 18 ## How do I scroll back up? 19 20 * Using a terminal multiplexer. 21 * `st -e tmux` using C-b [ 22 * `st -e screen` using C-a ESC 23 * Using the excellent tool of [scroll](https://git.suckless.org/scroll/). 24 * Using the scrollback [patch](https://st.suckless.org/patches/scrollback/). 25 26 ## I would like to have utmp and/or scroll functionality by default 27 28 You can add the absolute patch of both programs in your config.h 29 file. You only have to modify the value of utmp and scroll variables. 30 31 ## Why doesn't the Del key work in some programs? 32 33 Taken from the terminfo manpage: 34 35 If the terminal has a keypad that transmits codes when the keys 36 are pressed, this information can be given. Note that it is not 37 possible to handle terminals where the keypad only works in 38 local (this applies, for example, to the unshifted HP 2621 keys). 39 If the keypad can be set to transmit or not transmit, give these 40 codes as smkx and rmkx. Otherwise the keypad is assumed to 41 always transmit. 42 43 In the st case smkx=E[?1hE= and rmkx=E[?1lE>, so it is mandatory that 44 applications which want to test against keypad keys send these 45 sequences. 46 47 But buggy applications (like bash and irssi, for example) don't do this. A fast 48 solution for them is to use the following command: 49 50 $ printf '\033[?1h\033=' >/dev/tty 51 52 or 53 $ tput smkx 54 55 In the case of bash, readline is used. Readline has a different note in its 56 manpage about this issue: 57 58 enable-keypad (Off) 59 When set to On, readline will try to enable the 60 application keypad when it is called. Some systems 61 need this to enable arrow keys. 62 63 Adding this option to your .inputrc will fix the keypad problem for all 64 applications using readline. 65 66 If you are using zsh, then read the zsh FAQ 67 <http://zsh.sourceforge.net/FAQ/zshfaq03.html#l25>: 68 69 It should be noted that the O / [ confusion can occur with other keys 70 such as Home and End. Some systems let you query the key sequences 71 sent by these keys from the system's terminal database, terminfo. 72 Unfortunately, the key sequences given there typically apply to the 73 mode that is not the one zsh uses by default (it's the "application" 74 mode rather than the "raw" mode). Explaining the use of terminfo is 75 outside of the scope of this FAQ, but if you wish to use the key 76 sequences given there you can tell the line editor to turn on 77 "application" mode when it starts and turn it off when it stops: 78 79 function zle-line-init () { echoti smkx } 80 function zle-line-finish () { echoti rmkx } 81 zle -N zle-line-init 82 zle -N zle-line-finish 83 84 Putting these lines into your .zshrc will fix the problems. 85 86 ## How can I use meta in 8bit mode? 87 88 St supports meta in 8bit mode, but the default terminfo entry doesn't 89 use this capability. If you want it, you have to use the 'st-meta' value 90 in TERM. 91 92 ## I cannot compile st in OpenBSD 93 94 OpenBSD lacks librt, despite it being mandatory in POSIX 95 <http://pubs.opengroup.org/onlinepubs/9699919799/utilities/c99.html#tag_20_11_13>. 96 If you want to compile st for OpenBSD you have to remove -lrt from config.mk, and 97 st will compile without any loss of functionality, because all the functions are 98 included in libc on this platform. 99 100 ## The Backspace Case 101 102 St is emulating the Linux way of handling backspace being delete and delete being 103 backspace. 104 105 This is an issue that was discussed in suckless mailing list 106 <https://lists.suckless.org/dev/1404/20697.html>. Here is why some old grumpy 107 terminal users wants its backspace to be how he feels it: 108 109 Well, I am going to comment why I want to change the behaviour 110 of this key. When ASCII was defined in 1968, communication 111 with computers was done using punched cards, or hardcopy 112 terminals (basically a typewriter machine connected with the 113 computer using a serial port). ASCII defines DELETE as 7F, 114 because, in punched-card terms, it means all the holes of the 115 card punched; it is thus a kind of 'physical delete'. In the 116 same way, the BACKSPACE key was a non-destructive backspace, 117 as on a typewriter. So, if you wanted to delete a character, 118 you had to BACKSPACE and then DELETE. Another use of BACKSPACE 119 was to type accented characters, for example 'a BACKSPACE `'. 120 The VT100 had no BACKSPACE key; it was generated using the 121 CONTROL key as another control character (CONTROL key sets to 122 0 b7 b6 b5, so it converts H (code 0x48) into BACKSPACE (code 123 0x08)), but it had a DELETE key in a similar position where 124 the BACKSPACE key is located today on common PC keyboards. 125 All the terminal emulators emulated the difference between 126 these keys correctly: the backspace key generated a BACKSPACE 127 (^H) and delete key generated a DELETE (^?). 128 129 But a problem arose when Linus Torvalds wrote Linux. Unlike 130 earlier terminals, the Linux virtual terminal (the terminal 131 emulator integrated in the kernel) returned a DELETE when 132 backspace was pressed, due to the VT100 having a DELETE key in 133 the same position. This created a lot of problems (see [1] 134 and [2]). Since Linux has become the king, a lot of terminal 135 emulators today generate a DELETE when the backspace key is 136 pressed in order to avoid problems with Linux. The result is 137 that the only way of generating a BACKSPACE on these systems 138 is by using CONTROL + H. (I also think that emacs had an 139 important point here because the CONTROL + H prefix is used 140 in emacs in some commands (help commands).) 141 142 From point of view of the kernel, you can change the key 143 for deleting a previous character with stty erase. When you 144 connect a real terminal into a machine you describe the type 145 of terminal, so getty configures the correct value of stty 146 erase for this terminal. In the case of terminal emulators, 147 however, you don't have any getty that can set the correct 148 value of stty erase, so you always get the default value. 149 For this reason, it is necessary to add 'stty erase ^H' to your 150 profile if you have changed the value of the backspace key. 151 Of course, another solution is for st itself to modify the 152 value of stty erase. I usually have the inverse problem: 153 when I connect to non-Unix machines, I have to press CONTROL + 154 h to get a BACKSPACE. The inverse problem occurs when a user 155 connects to my Unix machines from a different system with a 156 correct backspace key. 157 158 [1] http://www.ibb.net/~anne/keyboard.html 159 [2] http://www.tldp.org/HOWTO/Keyboard-and-Console-HOWTO-5.html 160 161 ## But I really want the old grumpy behaviour of my terminal 162 163 Apply [1]. 164 165 [1] https://st.suckless.org/patches/delkey 166 167 ## Why do images not work in st (in programs such as w3m)? 168 169 This is a terrible hack that overdraws an image on top of the terminal emulator 170 window. It also relies on a very specific way the terminal draws it's contents. 171 172 A more proper (but limited way) would be using sixels. Which st doesn't 173 support. 174 175 ## BadLength X error in Xft when trying to render emoji 176 177 Xft makes st crash when rendering color emojis with the following error: 178 179 "X Error of failed request: BadLength (poly request too large or internal Xlib length error)" 180 Major opcode of failed request: 139 (RENDER) 181 Minor opcode of failed request: 20 (RenderAddGlyphs) 182 Serial number of failed request: 1595 183 Current serial number in output stream: 1818" 184 185 This is a known bug in Xft (not st) which happens on some platforms and 186 combination of particular fonts and fontconfig settings. 187 188 See also: 189 https://gitlab.freedesktop.org/xorg/lib/libxft/issues/6 190 https://bugs.freedesktop.org/show_bug.cgi?id=107534 191 https://bugzilla.redhat.com/show_bug.cgi?id=1498269 192 193 The solution is to remove color emoji fonts or disable this in the fontconfig 194 XML configuration. As an ugly workaround (which may work only on newer 195 fontconfig versions (FC_COLOR)), the following code can be used to mask color 196 fonts: 197 198 FcPatternAddBool(fcpattern, FC_COLOR, FcFalse); 199 200 Please don't bother reporting this bug to st, but notify the upstream Xft 201 developers about fixing this bug.