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Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell. The shell's name is an acronym for Bourne-Again SHell, a pun on the name of the Bourne shell that it replaces and the notion of being "born again".

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How do you check if a file ends in a certain file extension in bash? (lemmynsfw.com)

submitted 5 months ago* (last edited 5 months ago) by PenisWenisGenius@lemmynsfw.com to c/bash@programming.dev

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Seriously. There doesn't seem to be a way to do this. Every thing I ever try I just get bad substitution errors. The internet is full of people posting code that's supposed to compare file extensions but none of it works. I've spent all morning trying everything I could find. I already gave up and I'm making this progeam in python instead but now I'm curious. How tf do you actually compare file extensions? If I have a folder fill of files and I want to run a command only on the png files, there seems to be no way to actually do this.

If someone posts "[[ $file == *.txt ]]" I'm going to fucking scream because THAT DOES NOT WORK. IT'S NOT VAILD BASH CODE.

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[–] manicdave@feddit.uk 2 points 5 months ago (1 children)

ls returns a list of files, the pipe passes that list to grep. The grep only returns results that match the string txt$. The $ symbol represents an end of line.

[–] korthrun@lemmy.sdf.org 5 points 5 months ago* (last edited 5 months ago) (1 children)

That's my bad, I asked an incomplete question.

What does the approach of spawning a grep process and having ls send ALL of it's output to grep have over just passing a glob to ls?

Like:

$ ls /usr/share/*.lm

/usr/share/out-go.lm  /usr/share/ril.lm     /usr/share/rlhc-crack.lm   /usr/share/rlhc-d.lm   /usr/share/rlhc-java.lm  /usr/share/rlhc-julia.lm  /usr/share/rlhc-ocaml.lm  /usr/share/rlhc-rust.lm
/usr/share/ragel.lm   /usr/share/rlhc-c.lm  /usr/share/rlhc-csharp.lm  /usr/share/rlhc-go.lm  /usr/share/rlhc-js.lm    /usr/share/rlhc-main.lm   /usr/share/rlhc-ruby.lm

[–] manicdave@feddit.uk 2 points 5 months ago* (last edited 5 months ago)

Tbh, I didn't even realise you could do that. I'm just used to using grep and worked backwards. Thanks for pointing it out.