Is there a way to write a Bash function which aborts the whole execution, no matter how it is called?
I was using the "exit 1" statement in my Bash functions to terminate the whole script and it worked fine:
function func()
{
echo "Goodbye"
exit 1
}
echo "Function call will abort"
func
echo "This will never be printed"
But then I realized that it doesn't do the work when called like:
res=$(func)
I understand that I created a subshell and "exit 1" aborts that subshell and not the primary one....
But is there a way to write a function which aborts the whole execution, no matter how it is called? I just need to get the real return value (echoed by the function).
Solution 1:
What you could do, is register the top level shell for the TERM
signal to exit, and then send a TERM
to the top level shell:
#!/bin/bash
trap "exit 1" TERM
export TOP_PID=$$
function func()
{
echo "Goodbye"
kill -s TERM $TOP_PID
}
echo "Function call will abort"
echo $(func)
echo "This will never be printed"
So, your function sends a TERM
signal back to the top level shell, which is caught and handled using the provided command, in this case, "exit 1"
.
Solution 2:
You can use set -e
which exits if a command exits with a non-zero status:
set -e
func
set +e
Or grab the return value:
(func) || exit $?
Solution 3:
A child process can't force the parent process to close implicitly. You need to use some kind of signaling mechanism. Options might include a special return value, or perhaps sending some signal with kill
, something like
function child() {
local parent_pid="$1"
local other="$2"
...
if [[ $failed ]]; then
kill -QUIT "$parent_pid"
fi
}