Common shell script mistakes (2008)

Shout out to Shellcheck (http://www.shellcheck.net/), a linter for shell scripts

The single biggest shell script mistake is not handling whitespace in file names correctly, and it's almost impossible to do correctly if you have weird file names: embedded newlines, leading and trailing spaces, embedded tabs. Embedded quotes can be tricky too, especially if you're writing a script that generates a script. That bit, writing a script that generates a script, happens surprisingly often in bash. It's cheaper to pipe a stream to sed that converts it into a shell command…

Advice at a higher level: don’t try too hard to handle error cases in your scripts. The best shell scripts are a list of imperative instructions to get something done. If an error occurs, bail as early as possible and with a useful message. Don’t try any harder than that. For example: if ! complex_function then handle_error fi …doesn’t work as you’d expect because the “if” context changes the rules of set -e in complex_function. It’s much better to have…

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