#!/bin/bash

77 readers

1 users here now

A community to discuss about Bash.

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".

Keep discussion limited to Bash and projects around it. Feel free to share resources, self-projects, tutorials or any other cool stuff related to Bash.

Icon Attribution : Free Software Foundation, FAL, via Wikimedia Commons.

founded 10 months ago

MODERATORS

[email protected]

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

submitted 6 months ago* (last edited 6 months ago) by [email protected] to c/[email protected]

18 comments fedilink hide all child comments

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.

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 2 points 6 months ago (1 children)

What's the purpose of a pipe and an execution of "grep" here?

[–] [email protected] 2 points 6 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.

[–] [email protected] 5 points 6 months ago* (last edited 6 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

[–] [email protected] 2 points 6 months ago* (last edited 6 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.