Regexes Are Awesome

Let's say you download a useful bash script that uses bubblewrap to sandbox electron bloat like Signal. The script is great but, unfortunately, it uses "function blah { }" to define functions instead of "blah() { }". There are 19 such "functions" in this script. You could manually change all of them to the latter format. Or, you could use a regex in vim and change it in a few seconds.

:%s:^function \([[:alpha:]_]\+\) {:\1() {:g

"[[:alpha:]_]" matches an alphabet and the _ character. The "+" ensures to match multiple letters of this pattern. The ^ at the beginning ensures that the line starts with function.

We've surrounded the pattern we wrote with ( and ) which is called "grouping". All we did is "capture" that pattern because we'll need it later when we make the substitution we want. We didn't capture function and "{" because we want to remove them.

All that's left is to make the substitution with \1, our captured pattern, and () {.

Awesome.

Created: 2021-12-05

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