I wrote a tiny Bash script to find all the Mercurial changesets (starting from the tip) that contains the string passed in argument:
#!/bin/bash
CNT=$(hg tip | awk '{ print $2 }' | head -c 3)
while [ $CNT -gt 0 ]
do
echo rev $CNT
hg log -v -r$CNT | grep $1
let CNT=CNT-1
done
If I interrupt it by hitting ctrl-c, more often than not the command currently executed is "hg log" and it's that command that gets interrupted, but then my script continues.
I was then thinking of checking the return status of "hg log", but because I'm piping it into grep I'm not too sure as to how to go about it...
How should I go about exiting this script when it is interrupted? (btw I don't know if that script is good at all for what I want to do but it does the job and anyway I'm interested in the "interrupted" issue)
Turned out the way Ctrl-c works is quite simple — it's just a shortcut key for sending the interrupt (terminate) signal SIGINT to the current process running in the foreground. Once the process gets that signal, it's terminating itself and returns the user to the shell prompt.
Many signals are available in bash. The most common signal of bash is SIGINT (Signal Interrupt). When the user presses CTRL+C to interrupt any process from the terminal then this signal is sent to notify the system. Bash trap command.
If you are executing a Bash script in your terminal and need to stop it before it exits on its own, you can use the Ctrl + C combination on your keyboard.
How do I disable Control-C? You need to use the trap command which can enable or disable keyboard keys such as Crtl-C. SIGINT is Crtl-C and it is represented using number 2. Signal names are case insensitive and the SIG prefix is optional.
Place at the beginning of your script: trap 'echo interrupted; exit' INT
Edit: As noted in comments below, probably doesn't work for the OP's program due to the pipe. The $PIPESTATUS
solution works, but it might be simpler to set the script to exit if any program in the pipe exits with an error status: set -e -o pipefail
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