st

simple terminal
git clone git://git.suckless.org/st
Log | Files | Refs | README | LICENSE

FAQ (8275B)


      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 
     22 * `st -e tmux` using C-b [
     23 * `st -e screen` using C-a ESC
     24 
     25 ## Why doesn't the Del key work in some programs?
     26 
     27 Taken from the terminfo manpage:
     28 
     29 	If the terminal has a keypad that transmits codes when the keys
     30 	are pressed, this information can be given. Note that it is not
     31 	possible to handle terminals where the keypad only works in
     32 	local (this applies, for example, to the unshifted HP 2621 keys).
     33 	If the keypad can be set to transmit or not transmit, give these
     34 	codes as smkx and rmkx. Otherwise the keypad is assumed to
     35 	always transmit.
     36 
     37 In the st case smkx=E[?1hE= and rmkx=E[?1lE>, so it is mandatory that
     38 applications which want to test against keypad keys send these
     39 sequences.
     40 
     41 But buggy applications (like bash and irssi, for example) don't do this. A fast
     42 solution for them is to use the following command:
     43 
     44 	$ printf '\033[?1h\033=' >/dev/tty
     45 
     46 or
     47 	$ tput smkx
     48 
     49 In the case of bash, readline is used. Readline has a different note in its
     50 manpage about this issue:
     51 
     52 	enable-keypad (Off)
     53 		When set to On, readline will try to enable the
     54 		application keypad when it is called. Some systems
     55 		need this to enable arrow keys.
     56 
     57 Adding this option to your .inputrc will fix the keypad problem for all
     58 applications using readline.
     59 
     60 If you are using zsh, then read the zsh FAQ
     61 <http://zsh.sourceforge.net/FAQ/zshfaq03.html#l25>:
     62 
     63 	It should be noted that the O / [ confusion can occur with other keys
     64 	such as Home and End. Some systems let you query the key sequences
     65 	sent by these keys from the system's terminal database, terminfo.
     66 	Unfortunately, the key sequences given there typically apply to the
     67 	mode that is not the one zsh uses by default (it's the "application"
     68 	mode rather than the "raw" mode). Explaining the use of terminfo is
     69 	outside of the scope of this FAQ, but if you wish to use the key
     70 	sequences given there you can tell the line editor to turn on
     71 	"application" mode when it starts and turn it off when it stops:
     72 
     73 		function zle-line-init () { echoti smkx }
     74 		function zle-line-finish () { echoti rmkx }
     75 		zle -N zle-line-init
     76 		zle -N zle-line-finish
     77 
     78 Putting these lines into your .zshrc will fix the problems.
     79 
     80 ## How can I use meta in 8bit mode?
     81 
     82 St supports meta in 8bit mode, but the default terminfo entry doesn't
     83 use this capability. If you want it, you have to use the 'st-meta' value
     84 in TERM.
     85 
     86 ## I cannot compile st in OpenBSD
     87 
     88 OpenBSD lacks librt, despite it being mandatory in POSIX
     89 <http://pubs.opengroup.org/onlinepubs/9699919799/utilities/c99.html#tag_20_11_13>.
     90 If you want to compile st for OpenBSD you have to remove -lrt from config.mk, and
     91 st will compile without any loss of functionality, because all the functions are
     92 included in libc on this platform.
     93 
     94 ## The Backspace Case
     95 
     96 St is emulating the Linux way of handling backspace being delete and delete being
     97 backspace.
     98 
     99 This is an issue that was discussed in suckless mailing list
    100 <https://lists.suckless.org/dev/1404/20697.html>. Here is why some old grumpy
    101 terminal users wants its backspace to be how he feels it:
    102 
    103 	Well, I am going to comment why I want to change the behaviour
    104 	of this key. When ASCII was defined in 1968, communication
    105 	with computers was done using punched cards, or hardcopy
    106 	terminals (basically a typewriter machine connected with the
    107 	computer using a serial port).  ASCII defines DELETE as 7F,
    108 	because, in punched-card terms, it means all the holes of the
    109 	card punched; it is thus a kind of 'physical delete'. In the
    110 	same way, the BACKSPACE key was a non-destructive backspace,
    111 	as on a typewriter.  So, if you wanted to delete a character,
    112 	you had to BACKSPACE and then DELETE.  Another use of BACKSPACE
    113 	was to type accented characters, for example 'a BACKSPACE `'.
    114 	The VT100 had no BACKSPACE key; it was generated using the
    115 	CONTROL key as another control character (CONTROL key sets to
    116 	0 b7 b6 b5, so it converts H (code 0x48) into BACKSPACE (code
    117 	0x08)), but it had a DELETE key in a similar position where
    118 	the BACKSPACE key is located today on common PC keyboards.
    119 	All the terminal emulators emulated the difference between
    120 	these keys correctly: the backspace key generated a BACKSPACE
    121 	(^H) and delete key generated a DELETE (^?).
    122 
    123 	But a problem arose when Linus Torvalds wrote Linux. Unlike
    124 	earlier terminals, the Linux virtual terminal (the terminal
    125 	emulator integrated in the kernel) returned a DELETE when
    126 	backspace was pressed, due to the VT100 having a DELETE key in
    127 	the same position.  This created a lot of problems (see [1]
    128 	and [2]). Since Linux has become the king, a lot of terminal
    129 	emulators today generate a DELETE when the backspace key is
    130 	pressed in order to avoid problems with Linux. The result is
    131 	that the only way of generating a BACKSPACE on these systems
    132 	is by using CONTROL + H. (I also think that emacs had an
    133 	important point here because the CONTROL + H prefix is used
    134 	in emacs in some commands (help commands).)
    135 
    136 	From point of view of the kernel, you can change the key
    137 	for deleting a previous character with stty erase. When you
    138 	connect a real terminal into a machine you describe the type
    139 	of terminal, so getty configures the correct value of stty
    140 	erase for this terminal. In the case of terminal emulators,
    141 	however, you don't have any getty that can set the correct
    142 	value of stty erase, so you always get the default value.
    143 	For this reason, it is necessary to add 'stty erase ^H' to your
    144 	profile if you have changed the value of the backspace key.
    145 	Of course, another solution is for st itself to modify the
    146 	value of stty erase.  I usually have the inverse problem:
    147 	when I connect to non-Unix machines, I have to press CONTROL +
    148 	h to get a BACKSPACE. The inverse problem occurs when a user
    149 	connects to my Unix machines from a different system with a
    150 	correct backspace key.
    151 
    152 	[1] http://www.ibb.net/~anne/keyboard.html
    153 	[2] http://www.tldp.org/HOWTO/Keyboard-and-Console-HOWTO-5.html
    154 
    155 ## But I really want the old grumpy behaviour of my terminal
    156 
    157 Apply [1].
    158 
    159 [1] https://st.suckless.org/patches/delkey
    160 
    161 ## Why do images not work in st (in programs such as w3m)?
    162 
    163 This is a terrible hack that overdraws an image on top of the terminal emulator
    164 window. It also relies on a very specific way the terminal draws it's contents.
    165 
    166 A more proper (but limited way) would be using sixels. Which st doesn't
    167 support.
    168 
    169 ## BadLength X error in Xft when trying to render emoji
    170 
    171 Xft makes st crash when rendering color emojis with the following error:
    172 
    173 "X Error of failed request:  BadLength (poly request too large or internal Xlib length error)"
    174   Major opcode of failed request:  139 (RENDER)
    175   Minor opcode of failed request:  20 (RenderAddGlyphs)
    176   Serial number of failed request: 1595
    177   Current serial number in output stream:  1818"
    178 
    179 This is a known bug in Xft (not st) which happens on some platforms and
    180 combination of particular fonts and fontconfig settings.
    181 
    182 See also:
    183 https://gitlab.freedesktop.org/xorg/lib/libxft/issues/6
    184 https://bugs.freedesktop.org/show_bug.cgi?id=107534
    185 https://bugzilla.redhat.com/show_bug.cgi?id=1498269
    186 
    187 The solution is to remove color emoji fonts or disable this in the fontconfig
    188 XML configuration.  As an ugly workaround (which may work only on newer
    189 fontconfig versions (FC_COLOR)), the following code can be used to mask color
    190 fonts:
    191 
    192 	FcPatternAddBool(fcpattern, FC_COLOR, FcFalse);
    193 
    194 Please don't bother reporting this bug to st, but notify the upstream Xft
    195 developers about fixing this bug.