Display command in xterm titlebar

Question

My Bash Prompt is currently setting the xterm titlebar using the following sequence:

PS1='\033]0;\u@\h>\w\007'

Is there an easy way to display the current command in the titlebar. For example, if I am tailing a file using tail -f foo.log, I want my titlebar to say tail -f foo.log.

Answer 1

basically, you need:

trap 'echo -ne "\033]0;$BASH_COMMAND\007"' DEBUG

at the end of your .bashrc or similar. Took me a while to work this out -- see my answer here for more information :)

Answer 2

_{(Inspired by this SU answer)}

You can combine a couple bash tricks:

• If you trap a DEBUG signal, the handler is called before each command is executed
• The variable $BASH_COMMAND holds the currently executing command

So, trap DEBUG and have the handler set the title to $BASH_COMMAND:

trap 'echo -ne "\033]0;$BASH_COMMAND\007"' DEBUG

This will keep the title changed until something else changes it, but as long as your $PS1 stays the same it won't be a problem -- you start a command, the DEBUG handler changes the titlebar, and when the command finishes bash draws a new prompt and resets your titlebar again.

A useful tip found here (also where that SU answer came from) is to include:

set -o functrace

This will make bash propagate the DEBUG trap to any subshells you start; otherwise the titlebar won't be changed in them