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13

How do I check if command failed... with a pipe?

rated 0 times [ 13] [ 0] / answers: 1 / hits: 6233 / 2 Years ago, sun, april 3, 2022, 5:43:03

So I have a script like this:

somecommad | grep --invert-match something

I'd like to be able to conditionally run a different command if somecommand fails. Here's what I tried:

somecommand | grep --invert-match something || {

    echo 'Oops'

}

But that didn't work (the grep wasn't executed). What is the proper way to do this?

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ranquctive

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answered 2 Years ago looweets · Accepted Answer

@steeldriver mentioned in the comments that PIPESTATUS might work. I tried it, and it worked well. Here's what I did:

somecommand | grep --invert-match something

if [ "${PIPESTATUS[0]}" != "0" ]; then

    echo 'Oops'

fi

It runs the command as before, but then I have an if statement to look at the PIPESTATUS array. I only care about the first element, so that is the one I look at. I check it it failed (if the exit code is not 0), and it it did fail, run echo 'Oops'