Bash - Update terminal title by running a second command

Question

On my terminal in Ubuntu, I often run programs which keep running for a long time. And since there are a lot of these programs, I keep forgetting which terminal is for which

Answer 1

The OP asked for bash, but others might be interested to learn that (as mentioned above) this is indeed a lot easier using the zsh shell. Example:

# Set window title to command just before running it.
preexec() { printf "\x1b]0;%s\x07" "$1"; }

# Set window title to current working directory after returning from a command.
precmd() { printf "\x1b]0;%s\x07" "$PWD" }

In preexec, $1 contains the command as typed (requires shell history to be enabled, which seems to be a fair assumption), $2 the expanded command (shell aliases etc.) and $3 the "very expanded" command (shell function bodies). (more)

Answer 2

I have tested three method, all is OK, use any one for your pleasure.

export PROMPT_COMMAND='echo -ne "\033]2;$(history 1 | sed "s/^[ ]*[0-9]*[ ]*//g")\007"'

trap 'echo -ne "\033]2;$(history 1 | sed "s/^[ ]*[0-9]*[ ]*//g")\007"' DEBUG

trap 'echo -ne "\e]0;"; echo -n $BASH_COMMAND; echo -ne "\a"' DEBUG

please note if use $BASH_COMMAND, it don't recognize bash alias, and use PROMPT_COMMAND show finished command, but use trap show running command.

Answer 3

Try this:

trap 'echo -ne "\033]2;$(history 1 | sed "s/^[ ]*[0-9]*[ ]*//g")\007"' DEBUG

Thanks to the history 1 it works even with complicated expressions like:

true && (false); echo $? | cat

For which approaches relying on $BASH_COMMAND or $@ fail. For example simon's displays:

true | echo $? | cat

Thanks to Gilles and simon for providing inspiration.

Answer 4

I'm doing something like this, to show my pwd in the title, which could be modified to do whatever you want to do with the title:

function title { echo -en "\033]2;$1\007"; }
function cd { dir=$1; if [ -z "$dir" ]; then dir=~; fi; builtin cd "$dir" && title `pwd`; }

I just threw this in my ~/.bash_aliases.

Update

I ran into strange bugs with my original answer. I ended up picking apart the default Ubuntu PS1 and breaking it into parts only to realize one of the parts was the title:

# simple prompt
COLOR_YELLOW_BOLD="\[\033[1;33m\]"
COLOR_DEFAULT="\[\033[0m\]"
TITLE="\[\e]0;\u@\h:\w\a\]"
PROMPT="\w\n$ "
HUH="${debian_chroot:+($debian_chroot)}"
PS1="${COLOR_YELLOW_BOLD}${TITLE}${HUH}${PROMPT}${COLOR_DEFAULT}"

Without breaking into variables, it would look like this:

PS1="\[\033[1;33m\]\[\e]0;\u@\h:\w\a\]${debian_chroot:+($debian_chroot)}\w\n$ \[\033[0m\]"

Answer 5

You can set up bash such that it sends a certain escape sequence to the terminal every time it starts an external program. If you use the escape sequence that terminals use to update their titles, your problem should be solved.

I have used that before, so I know it is possible. but I cannot remember it off the top of my head and do not have time to research the details right now, though.

Answer 6

I see what stoutie is trying to do, except it's a lot more work than needed. And doesn't cause all sorts of other potentially bad things that can occur as a result of redefining 'cd' and putting in all of that testing just to change directories. Bash has built in support for most of this.

You can put this in your .bashrc anywhere after you set your current PS1 prompt (this way it just prepends it)

# If this is an xterm set the titlebar to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac