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0 pointsCerium3y ago0 comments

"Use [[ ]] for conditions"

Oh how I hate the double square bracket. It is the source of many head scratching bugs and time wasted. "The script works in my machine!" It doesn't work in production where we only have sh. It won't exit due to an error, the if statement will gobble the error. You only find the bug after enough bug reports hit that particular condition.

After a couple shots to the foot I avoid double square brackets at all cost.

0 comments

therealjumbo3y ago

This should be fixed with a shebang and shellcheck. If your shebang is #!/bin/sh, shellcheck will complain loudly about bash-isms. If production is sh and doesn't have bash, there's quite a few other bash-ism you want to check for. You can run shellcheck in CI to check your scripts and return non-zero if they aren't clean, and you can force off warnings for lines that are ok.

EDIT: I should have said, "could be fixed once and for all", "should" is just my opinion.

kdmccormick3y ago

If I may ask, why do you only have sh in production?

Cpoll3y ago

A common containerization philosophy is to use a bare-minimum base image and add only what you need. Something like an Alpine container doesn't come with Bash.

0xbadcafebee3y ago

Alpine docker container only comes with ash shell by default. If you don't use any Bash-isms, you can just write a POSIX shell script. Otherwise if you have many containers from many different sources, you might have to bake all new containers just to add Bash to them.

CeriumOP3y ago

In this case production is a fleet of embedded devices.

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