I have scoured the internet for an explanation, but the cryptic terseness of t_ts and t_fs makes it impossible to find helpful information about how I can expect systems to work.
Here is an overview of my existing knowledge, and I'd love it if someone wise could fill in the last few dots...
I "started" somewhere here: http://tldp.org/HOWTO/Xterm-Title-3.html
I verified running this in my bash shell (where the ^[ is produced by Ctrl+V,Esc):
printf "^[]0;testTITLEzzz"
This works. It works to set the title on a raw terminal and it works to set the title for a pane in tmux.
Note! I did not need to use a trailing "\007" char.
Inside my .vimrc, when I use set title, and set a titlestring, it always correctly sets the raw terminal title correctly, but failed to set the tmux pane title.
Once I set this, though (same thing with the ^[, it is a raw ESC char):
if &term == "tmux-256color-italic"
set t_ts=^[]0;
set t_fs=
endif
It started to work for setting the tmux pane title. I rejoiced.
Now the trouble I have is how to turn this procedural knowledge into practical knowledge that I can use in the future.
Question 1
I looked up the help in vim, I get this:
t_ts set window title start (to status line) t_ts 't_ts'
t_fs set window title end (from status line) t_fs 't_fs'
I don't know what "status line" means here.
Question 2
I want to know how these terminal-output-codes as documented in vim correspond to the rest of the xterm world, or whatever I should call it.
For example I can query infocmp to get my current terminal config and xterm terminal config's values:
$ infocmp xterm
# Reconstructed via infocmp from file: /lib/terminfo/x/xterm
xterm|xterm-debian|X11 terminal emulator,
am, bce, km, mc5i, mir, msgr, npc, xenl,
colors#8, cols#80, it#8, lines#24, pairs#64,
acsc=``aaffggiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
bel=^G, blink=\E[5m, bold=\E[1m, cbt=\E[Z, civis=\E[?25l,
clear=\E[H\E[2J, cnorm=\E[?12l\E[?25h, cr=\r,
csr=\E[%i%p1%d;%p2%dr, cub=\E[%p1%dD, cub1=^H,
cud=\E[%p1%dB, cud1=\n, cuf=\E[%p1%dC, cuf1=\E[C,
cup=\E[%i%p1%d;%p2%dH, cuu=\E[%p1%dA, cuu1=\E[A,
cvvis=\E[?12;25h, dch=\E[%p1%dP, dch1=\E[P, dim=\E[2m,
dl=\E[%p1%dM, dl1=\E[M, ech=\E[%p1%dX, ed=\E[J, el=\E[K,
el1=\E[1K, flash=\E[?5h$<100/>\E[?5l, home=\E[H,
hpa=\E[%i%p1%dG, ht=^I, hts=\EH, ich=\E[%p1%d#,
il=\E[%p1%dL, il1=\E[L, ind=\n, indn=\E[%p1%dS,
invis=\E[8m, is2=\E[!p\E[?3;4l\E[4l\E>, kDC=\E[3;2~,
kEND=\E[1;2F, kHOM=\E[1;2H, kIC=\E[2;2~, kLFT=\E[1;2D,
kNXT=\E[6;2~, kPRV=\E[5;2~, kRIT=\E[1;2C, kb2=\EOE, kbs=^?,
kcbt=\E[Z, kcub1=\EOD, kcud1=\EOB, kcuf1=\EOC, kcuu1=\EOA,
kdch1=\E[3~, kend=\EOF, kent=\EOM, kf1=\EOP, kf10=\E[21~,
kf11=\E[23~, kf12=\E[24~, kf13=\E[1;2P, kf14=\E[1;2Q,
kf15=\E[1;2R, kf16=\E[1;2S, kf17=\E[15;2~, kf18=\E[17;2~,
kf19=\E[18;2~, kf2=\EOQ, kf20=\E[19;2~, kf21=\E[20;2~,
kf22=\E[21;2~, kf23=\E[23;2~, kf24=\E[24;2~,
kf25=\E[1;5P, kf26=\E[1;5Q, kf27=\E[1;5R, kf28=\E[1;5S,
kf29=\E[15;5~, kf3=\EOR, kf30=\E[17;5~, kf31=\E[18;5~,
kf32=\E[19;5~, kf33=\E[20;5~, kf34=\E[21;5~,
kf35=\E[23;5~, kf36=\E[24;5~, kf37=\E[1;6P, kf38=\E[1;6Q,
kf39=\E[1;6R, kf4=\EOS, kf40=\E[1;6S, kf41=\E[15;6~,
kf42=\E[17;6~, kf43=\E[18;6~, kf44=\E[19;6~,
kf45=\E[20;6~, kf46=\E[21;6~, kf47=\E[23;6~,
kf48=\E[24;6~, kf49=\E[1;3P, kf5=\E[15~, kf50=\E[1;3Q,
kf51=\E[1;3R, kf52=\E[1;3S, kf53=\E[15;3~, kf54=\E[17;3~,
kf55=\E[18;3~, kf56=\E[19;3~, kf57=\E[20;3~,
kf58=\E[21;3~, kf59=\E[23;3~, kf6=\E[17~, kf60=\E[24;3~,
kf61=\E[1;4P, kf62=\E[1;4Q, kf63=\E[1;4R, kf7=\E[18~,
kf8=\E[19~, kf9=\E[20~, khome=\EOH, kich1=\E[2~,
kind=\E[1;2B, kmous=\E[M, knp=\E[6~, kpp=\E[5~,
kri=\E[1;2A, mc0=\E[i, mc4=\E[4i, mc5=\E[5i, meml=\El,
memu=\Em, op=\E[39;49m, rc=\E8, rep=%p1%c\E[%p2%{1}%-%db,
rev=\E[7m, ri=\EM, rin=\E[%p1%dT, ritm=\E[23m, rmacs=\E(B,
rmam=\E[?7l, rmcup=\E[?1049l\E[23;0;0t, rmir=\E[4l,
rmkx=\E[?1l\E>, rmm=\E[?1034l, rmso=\E[27m, rmul=\E[24m,
rs1=\Ec, rs2=\E[!p\E[?3;4l\E[4l\E>, sc=\E7,
setab=\E[4%p1%dm, setaf=\E[3%p1%dm,
setb=\E[4%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
setf=\E[3%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
sgr=%?%p9%t\E(0%e\E(B%;\E[0%?%p6%t;1%;%?%p5%t;2%;%?%p2%t;4%;%?%p1%p3%|%t;7%;%?%p4%t;5%;%?%p7%t;8%;m,
sgr0=\E(B\E[m, sitm=\E[3m, smacs=\E(0, smam=\E[?7h,
smcup=\E[?1049h\E[22;0;0t, smir=\E[4h, smkx=\E[?1h\E=,
smm=\E[?1034h, smso=\E[7m, smul=\E[4m, tbc=\E[3g,
u6=\E[%i%d;%dR, u7=\E[6n, u8=\E[?%[;0123456789]c,
u9=\E[c, vpa=\E[%i%p1%dd,
$ infocmp
# Reconstructed via infocmp from file: /home/slu/.terminfo/t/tmux-256color-italic
tmux-256color-italic|screen with 256 colors and italic,
am, km, mir, msgr, xenl,
colors#0x100, cols#80, it#8, lines#24, pairs#0x7fff,
acsc=++\,\,--..00``aaffgghhiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
bel=^G, blink=\E[5m, bold=\E[1m, cbt=\E[Z, civis=\E[?25l,
clear=\E[H\E[J, cnorm=\E[34h\E[?25h, cr=\r,
csr=\E[%i%p1%d;%p2%dr, cub=\E[%p1%dD, cub1=^H,
cud=\E[%p1%dB, cud1=\n, cuf=\E[%p1%dC, cuf1=\E[C,
cup=\E[%i%p1%d;%p2%dH, cuu=\E[%p1%dA, cuu1=\EM,
cvvis=\E[34l, dch=\E[%p1%dP, dch1=\E[P, dim=\E[2m,
dl=\E[%p1%dM, dl1=\E[M, ed=\E[J, el=\E[K, el1=\E[1K,
enacs=\E(B\E)0, flash=\Eg, home=\E[H, hpa=\E[%i%p1%dG,
ht=^I, hts=\EH, ich=\E[%p1%d#, il=\E[%p1%dL, il1=\E[L,
ind=\n, indn=\E[%p1%dS, is2=\E)0, kbs=^?, kcbt=\E[Z,
kcub1=\EOD, kcud1=\EOB, kcuf1=\EOC, kcuu1=\EOA,
kdch1=\E[3~, kend=\E[4~, kf1=\EOP, kf10=\E[21~,
kf11=\E[23~, kf12=\E[24~, kf2=\EOQ, kf3=\EOR, kf4=\EOS,
kf5=\E[15~, kf6=\E[17~, kf7=\E[18~, kf8=\E[19~, kf9=\E[20~,
khome=\E[1~, kich1=\E[2~, kmous=\E[M, knp=\E[6~, kpp=\E[5~,
nel=\EE, op=\E[39;49m, rc=\E8, rev=\E[7m, ri=\EM,
ritm=\E[23m, rmacs=^O, rmcup=\E[?1049l, rmir=\E[4l,
rmkx=\E[?1l\E>, rmso=\E[27m, rmul=\E[24m,
rs2=\Ec\E[?1000l\E[?25h, sc=\E7,
setab=\E[%?%p1%{8}%<%t4%p1%d%e%p1%{16}%<%t10%p1%{8}%-%d%e48;5;%p1%d%;m,
setaf=\E[%?%p1%{8}%<%t3%p1%d%e%p1%{16}%<%t9%p1%{8}%-%d%e38;5;%p1%d%;m,
sgr=\E[0%?%p6%t;1%;%?%p1%t;3%;%?%p2%t;4%;%?%p3%t;7%;%?%p4%t;5%;%?%p5%t;2%;m%?%p9%t\016%e\017%;,
sgr0=\E[m\017, sitm=\E[3m, smacs=^N, smcup=\E[?1049h,
smir=\E[4h, smkx=\E[?1h\E=, smso=\E[7m, smul=\E[4m,
tbc=\E[3g, vpa=\E[%i%p1%dd,
Nothing seems to line up with ts or fs.
At this point I don't think that the 2 letter codes map together, which is something that I have suspected for years.
Furthermore, since I learned that emitting <Esc>]0; followed by a string works to set the title, through my testing, I see that this always works regardless of the terminal capabilities that are specified in $TERM. This makes me question if looking at infocmp and wondering about whether something specified here is relevant to my ability to control the title.
Though, honestly, I hardly understand what the significance of the $TERM env var even is, aside from that programs such as vim and less complain if I haven't tic'd a terminfo file corresponding to the current value of $TERM. Again, just procedural knowledge, and I'm seeking something a little deeper and meaningful.
Question 3
Now that I've found a combination of configuration that allows tmux's pane titles to be set properly by vim, I wonder what it was that vim was sending prior to my setting of t_ts that worked on raw terminals but did not work for tmux. I know there is a way to trick vim into thinking i'm running it interactively while piping all of its output into a binary file, and then go hex spelunking for the difference in codes, but I have forgotten how this is done, and suspect that there is a less painful way to find out.
Question 4
It is entirely unclear what i should set, if anything, for t_fs, and this touches also upon the question of why the \007 BEL character is not necessary to terminate the title sequence. Why is it not necessary, and what should I expect will terminate the sequence? A newline?
You definitely need the trailing \007 (or \033\\) or some terminals will stop responding waiting for the end of the sequence. Did you try this inside tmux? tmux has a timeout to prevent panes hanging, but most other terminals do not. If you try it in xterm without the \007, it will hang.
For information on the title setting sequences themselves, look at https://invisible-island.net/xterm/ctlseqs/ctlseqs.html (title setting is OSC 0 and 2 - look under "Operating System Commands").
ts and fs are termcap names (terminfo is tsl/fsl) meaning "to status line" and "from status line" (as the name implies, infocmp is showing you terminfo, not termcap). These are somewhat historical from the days when hardware terminals had a separate status line, but in recent years have been reused sometimes for the X terminal title. Look at the "Status Lines" section in terminfo(5) for some bits about status line capabilities. In practice, tsl and fsl are not often provided or used and instead most applications look at the XT capability ("xterm titles") to work out if they should use the OSC sequences. XT is an extension capability - you need to use "infocmp -x" to see it.
You can always set the title inside tmux using the OSC sequences, by default the title (#{pane_title} format) is shown in quotes in status-right. tmux will not also set the external terminal title (the terminal tmux is running in) unless the set-titles option is on. The set-titles-string option controls the format of the title tmux sets (by default it includes the active pane's title and some other information). set-titles will only work if TERM outside tmux specifies an entry that contains XT or tsl/fsl (xterm does have XT).
I don't know how to configure vim to set the title but it seems like you are on the right track there with t_ts and t_fs - it seems like vim is using the tsl/fsl but using the termcap names (probably a legacy from vi which was started long before terminfo existed).
I can give you a brief description of how it works:
termcap was originally written in the 70s to allow vi to run on different (hardware) terminals;
terminfo was written as a replacement in the 80s to fix a number of problems and limitations with termcap;
both are still used (terminfo much more commonly) for both software and hardware terminals;
they both work in a similar way - there is a database of named entries (like "xterm" or "tmux-256color") which give a set of named capabilities of the terminal; some capabilities are flags (eg "XT") or numbers (eg "colors") but most are strings which specify the sequence an application should send to a terminal to make something happen (eg "cuu1" make the cursor move one line up - "\033[A" on vt100-compatible terminals);
termcap has short most two-character names, terminfo tend to be longer; termcap has a small limit of 1024 bytes on the length of a database entry so it is often missing many capabilities that terminfo has;
TERM is set to the name of the termcap or terminfo entry the application should look for in the database;
the terminfo database is maintained and shipped as part of ncurses (a library for drawing to the terminal which is used by many terminal applications); the termcap database is generated from terminfo using tic.
There isn't really a single source with all the information put together. For the escape sequences, https://vt100.net/ has a lot of manuals for old hardware terminals (much of which is now irrelevent however) and the link I gave above for xterm documents the escape sequences supported by xterm and most other modern terminal emulators support a subset of these (almost all terminals still around are vt100-compatible and xterm is the de facto standard terminal). ncurses has some manuals: terminfo(5) and termcap(5). There is an O'Reilly book called "termcap and terminfo" which covers much as well, but it was written in the late 80s so some of it is out of date.
Simply put, I know you can do ctrl+v+tab to insert a physically real tab character in a bash statement. But how do I do the same for iTerm?
The answer was to hit control+v, then tab afterwards, not all together! Hope this helps someone.
It's not iTerm, but your shell that affects how you''re able to insert a tab.
First, make sure you're in BASH shell: Type the following command:
$ echo $RANDOM $BASH_VERSINFO
23714 3
The first is a random number, and the second should be the BASH Version number. If you get a blank line or just a random number, you're not in the BASH shell, and that's probably one of your issues.
Another thing is to execute this command:
$ set -o
allexport off
braceexpand on
emacs on
errexit off
errtrace off
[...]
privileged off
verbose off
vi off
trace off
The two lines of interest is the emacs and the vi lines. One of those should be on. If they're both off, you can't do the Ctrl-V-Tab to insert a tab character.
When the vi mode is on, it should be Ctrl-V-Tab like you said. With emacs mode on, it is either Ctrl-V-tab, or possibly Ctrl-Q-tab.
However, this isn't an iTerm thing, this is your shell that's doing it.
If by a "physically real tab character" you mean sending the tab hex code (0x09) to the shell, then you can do this in iTerm by pressing Ctrl + Tab (⌃ ⇥).
This is the default setting, although you can change it (as well as add other hex code values to send) in iTerm > Preferences > Profiles > Keys.
I'm not certain why you're comparing a "bash statement" with iTerm. You write bash scripts in iTerm. Which means, assuming you're writing your scripts in iTerm, you're already doing what you want.
I'll assume you mean scripting in vi vs command line. The way I get literal characters on the command line is by using vi editing mode. Do set -o vi. Then you can use ctrl+v followed by tab in the manner that you're used to.
IMO, using vi editing mode comes with a slew of other pluses like searching your history, faster navigation, etc. So you could just add it to your .bashrc if you wanted and use it all the time.
One should also try Ctl + V Ctl + I. It is working in konsole where Ctl+V+Tab deosn't work.
If I do something like:
$ cat /bin/ls
into my terminal, I understand why I see a bunch of binary data, representing the ls executable. But afterwards, when I get my prompt back, my own keystrokes look crazy. I type "a" and I get a weird diagonal line. I type "b" and I get a degree symbol.
Why does this happen?
Because somewhere in your binary data were some control sequences that your terminal interpreted as requests to, for example, change the character set used to draw. You can restore everything to normal like so:
reset
Just do a copy-paste:
echo -e '\017'
to your bash and characters will return to normal. If you don't run bash, try the following keystrokes:
<Ctrl-V><Ctrl-O><Enter>
and hopefully your terminal's status will return to normal when it complains that it can't find either a <Ctrl-V><Ctrl-O> or a <Ctrl-O> command to run.
<Ctrl-N>, or character 14 —when sent to your terminal— orders to switch to a special graphics mode, where letters and numbers are replaced with symbols. <Ctrl-O>, or character 15, restores things back to normal.
The terminal will try to interpret the binary data thrown at it as control codes, and garble itself up in the process, so you need to sanitize your tty.
Run:
stty sane
And things should be back to normal. Even if the command looks garbled as you type it, the actual characters are being stored correctly, and when you press return the command will be invoked.
You can find more information about the stty command here.
You're getting some control characters piped into the shell that are telling the shell to alter its behavior and print things differently.
VT100 is pretty much the standard command set used for terminal windows, but there are a lot of extensions. Some control character set used, keyboard mapping, etc.
When you send a lot of binary characters to such a terminal, a lot of settings change. Some terminals have options to 'clear' the settings back to default, but in general they simply weren't made for binary data.
VT100 and its successors are what allow Linux to print in color text (such as colored ls listings) in a simple terminal program.
-Adam
If you really must dump binary data to your terminal, you'd have much better luck if you pipe it to a pager like less, which will display it in a slightly more readable format. (You may also be interested in strings and od, both can be useful if you're fiddling around with binary files.)