Here's a #bash pop quiz.

[vwbusguy@mastodon.online]

@gnemmi https://mastodon.online/@vwbusguy/113768832948629788

[vwbusguy@mastodon.online]

@me

Scott Williams 🐧 (@[email protected])

Content warning: The answer

Mastodon (mastodon.online)

[decathorpe@mastodon.social]

@vwbusguy thanks - one more reason for why I think bash is cursed

[vwbusguy@mastodon.online]

@decathorpe They're all cursed.

[rl_dane@polymaths.social]

@decathorpe @vwbusguy

Disagree. The whole point of the [[ ]] syntax is to examine and compare strings (and also filenames). There's no expectation of numerical or boolean analysis.

Now, if you said that bash is cursed because of the string substitution syntax, I'm with you on that one. Its horrifying.

[vwbusguy@mastodon.online]

@rl_dane @decathorpe I disagree. If you `man test` you'll see that numerical analysis is indeed supported and I use it regularly as a way to evaluate timestamps (converting to epoch seconds and using gt, lt, etc).

Here's an example of where I use it for both boolean and numerical analysis:

Calculates a new serial for a bind zone SOA. Assumes single zone per file.

Calculates a new serial for a bind zone SOA. Assumes single zone per file. - calculate_new_bind_serial.sh

Gist (gist.github.com)

[rl_dane@polymaths.social]

@vwbusguy @decathorpe

But test is analogous to [ ], not [[ ]].

[vwbusguy@mastodon.online]

@rl_dane @decathorpe [[ supports everything [ does. [[ is the bash-ism where [ is POSIX, and test in bash is a built-in, IIRC. None of this negates what I said in my previous post.

[rl_dane@polymaths.social]

@vwbusguy @decathorpe

My understanding is that test | [ ] was branched off into [[ ]] for string/filename analysis/comparison, and (( )) for numerical operations.

[[ ]] does seem to retain the legacy -gt | -lt operators of test | [ ], which is kinda cursed, admittedly.

[vwbusguy@mastodon.online]

@rl_dane @decathorpe No, what [[ adds is stuff like && and || for and/or logic and using ! for negation. It supports the same evals as test, and I should also note that "test", [, [[ are built-ins for bash, so it's not actually calling the test binary in a script unless you give the full path to it.

[ddlyh@topspicy.social]

@rl_dane
I just use `test` directly for everything as it makes more sense, so the above would be `test ! -z 1 && echo "true" || echo "false"`, which is actually readable!
@vwbusguy @decathorpe

[vwbusguy@mastodon.online]

@ddlyh @rl_dane @decathorpe test -n would be the equivalent one in this case.