Bash - run one script when previous is sucessful else run another script?

Question

I think my question is similar to this one but with one extrat step - say I have 3 scripts:

main_script.sh
report_success.sh
report_failure.sh

How can I do something like this pseudo-code does:

if (main_script.sh finished without error):
run report_success.sh
else:
run report_failure.sh

?

Thanks!

I guess you are aware tht the syntax you show is not bash. It looks like python. — schrodingerscatcuriosity, Aug 20 '19 at 19:08

score 5 · Answer 1 · edited Aug 20 '19 at 21:20

5

if main_script.sh; then
    report_success.sh
else
    report_failure.sh
fi

This uses the exit status of main_script.sh to determine whether it was successful (exit status 0) or not (exit status non-zero) and then runs the appropriate report script.

edited Aug 20 '19 at 21:20

Kusalananda

333,661

answered Aug 20 '19 at 19:18

dhanlin

61

score 2 · Accepted Answer · answered Aug 20 '19 at 19:19

2

Assuming your main_script.sh is fairly standard and passes a 0 for a successful run and 1 for an unsuccessful run, you can probe the status via $? like so:

./main_script.sh
if [ $? -eq 0 ]; then
    ./report_success.sh
else
    ./report_failure.sh
fi

answered Aug 20 '19 at 19:19

Jason K Lai

534

There is almost never a reason to compare or even use $? directly, unless you need to save it for later (which you don't need to here). – Kusalananda Aug 20 '19 at 21:15

score 2 · Answer 3 · answered Aug 20 '19 at 19:58

2

It's as simple as this:

true && echo ok || echo fail

false && echo ok || echo fail

A typical command may return null (as true does) or may return not null (as false does) depending on whether the operation succeeded or failed.

./main_script.sh && ./report_success.sh || ./report_failure.sh

If you had to run several commands for the ok or fail case, use braces. No need for several scripts:

./main_script.sh && { echo ok ; echo ok2 } || { echo fail ; echo fail2 ; }

answered Aug 20 '19 at 19:58

Janka

486

Note that your commands with && and || would run ./report_failure.sh if either of ./main_script.sh or ./report_success.sh failed. This is not the same thing as an explicit if-then-else. – Kusalananda Aug 20 '19 at 21:14
Well, yes. But failure of the success report is a failure, too. – Janka Aug 20 '19 at 21:33

Bash - run one script when previous is sucessful else run another script?

3 Answers3