Mikrobitti on tietotekniikkaan erikoistunut lehti, joka antaa syvällistä tietoa laitteista, palveluista ja ilmiöistä. Mikrobitissä testataan ja vertaillaan tietotekniikan kiinnostavimmat tuotteet.
Is there not also a way to disallow empty variables in the script, I think it is set -u? Then you don’t have to keep thinking “should I add a :? here because if empty it may lead to disaster” all the time. Might be even safer.
TL;DR: e aborts the whole script on a non-zero error. u aborts when using an undefined variable. -o pipefail aborts a piped compound command when one of the piped commands fail.
Any other way lies madness. Or erasing the whole filesystem apparently!
Yes! But -u is for undefined variables. It won’t stop a defined variable with an empty value. E.g foo="".
Also ? and :? have the advantage of telling you right then and there where the variable use is that it must be defined or not empty… having to trek back to (likely) the top of the script to check is easily forgotten.
Is there not also a way to disallow empty variables in the script, I think it is
set -u? Then you don’t have to keep thinking “should I add a:?here because if empty it may lead to disaster” all the time. Might be even safer.set -euo pipefailat the top of every script makes stuff a lot safer. Explanation here.Yep! I always do this too.
TL;DR:
eaborts the whole script on a non-zero error.uaborts when using an undefined variable.-o pipefailaborts a piped compound command when one of the piped commands fail.Any other way lies madness. Or erasing the whole filesystem apparently!
Yes! But
-uis for undefined variables. It won’t stop a defined variable with an empty value. E.gfoo="".Also
?and:?have the advantage of telling you right then and there where the variable use is that it must be defined or not empty… having to trek back to (likely) the top of the script to check is easily forgotten.