Pressing Ctrl-C stops bash script, but don't stop PHP script called by the script

Question

I need to run a few scripts every few minutes. The logic was made in PHP, and it's working great. To keep things together I've made the bash script below, which also runs fine.

#!/bin/bash calculaDiff() { DIFF=0 while [ "$DIFF" -eq "0" ]; do DIFF=`php calculaDiff.php` done; } # need to calculate pending diffs calculaDiff # main loop while true; do CAPTURA=`php capturaRelatorio.php` if [ "$CAPTURA" -eq "0" ]; then calculaDiff fi VERIFICA=`php verificaLimites.php` done 

The script capturaRelatorio.php has a sleep inside it because I can only process it every N minutes. It will print a message saying that it's sleeping for S seconds so I can monitor it.

If I call the bash script and press Ctrl+C at this time, while it's sleeping, it kills the bash script, but doesn't kill the called php script. I understand that there's a different process running it.

So, is there a way to kill the bash script and every "child"? Or should I go with another approach to run these scripts?

Answer 1

From this answer: bash - How to kill all subprocesses of shell? - Stack Overflow.

If you only care about killing direct children, you should be able to do

pkill -P $$ 

-P says

-P, --parent ppid,... Only match processes whose parent process ID is listed. 

And $$ means the PID of the current process.

If you need to kill child processes and any processes they may start (grandchildren, and so on), you should be able to use the function that is in a different answer to that question:

kill_descendant_processes() { local pid="$1" local and_self="${2:-false}" if children="$(pgrep -P "$pid")"; then for child in $children; do kill_descendant_processes "$child" true done fi if [[ "$and_self" == true ]]; then kill "$pid" fi } 

Like this

kill_descendant_processes $$ true 

Which will kill the current process and all descendants. You will probably want to call this from a trap handler. That is, when you press ctrl+c, your script will be sent SIGINT and you can catch that signal and handle it. For example:

trap cleanup INT cleanup() { kill_descendant_processes $$ true } 

Answer 2

You can update the bash script to trap ctrl+c:

trap control_c SIGINT function control_c() { echo "## Trapped CTRL-C" ps -ef | grep php | grep -v grep | awk '{ print $2 }' > php.kill for i in $(cat php.kill) do kill -9 $i > /dev/null done rm php.kill }