Post your Command line tricks

[rhowaldt]

was looking for a simple way to save my MP3 files (titles) to a textfile. i tried

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ls *mp3 > mp3.txt

but since my ls is set in my .bashrc to default to colors, that would include all the color escapecodes and make a right mess. so, looking through the ls manpage, i found you can undo that like so:

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ls --color=never *mp3 > mp3.txt

and i ended up with a nice list to share with people or as a reminder for when you are at somebody's place and trying to remember that one song you loved but you are too stoned to do so :)

[machinebacon]

env -i ls *mp3 > mp3.txt

:D just a guess

[rhowaldt]

^ damn that's good. didn't know that one. although of course your solution is more bloated :P

[wuxmedia]

^ WTF? Are all your mp3's loose in one folder? OCD my ass.
I just get an error.
You want bloat?

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find | cut -c 3- | env -i egrep '\.(mpc|mp4|mp3|flac)$' > mp3.txt

Yeah I couldn't get regex to play nice in find -shock!

EDIT added quote, to make it work 8)

[rhowaldt]

^ nope, they aren't. in fact, the *mp3 is inaccurate for my needs. my mp3s are in directories inside directories inside directories and so forth. ls * works recursively but only one directory down, so i might need something like your solution for finding *every* mp3. in my use-case however i just wanted one directory :)

[wuxmedia]

that's what I thought. good idea, to have a list.
I think the above goes as recursive as it can. plus it prints the path too.

[GekkoP]

^ doesn't it lack a quote at the end of egrep? :)

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find | cut -c 3- | env -i egrep '\.(mpc|mp4|mp3|flac)$' > mp3.txt

[pidsley]

um, guys, I have ls defined like this in my .zshrc (and .bashrc)

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alias ls='ls -F --color=auto --group-directories-first'

and I get colored output in a terminal, but I don't see any escape characters in the file if I do "ls > file".

from the ls man page:

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With --color=auto, ls emits color codes only when standard output is connected to a terminal.

So no escape codes if you redirect stdout to a file.

Another handy trick for things like this is the "command" builtin. From "help command":

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 Runs COMMAND with ARGS suppressing  shell function lookup, or display
    information about the specified COMMANDs.  Can be used to invoke commands
    on disk when a function with the same name exists.

So, for example, if you have "cp" aliased to run "cp -v" and then you decide you in fact want to run cp in non-verbose mode, you can use "command cp" to run the native cp without invoking your alias.

Finally, if you get really stuck and need a plain command (like somehow you broke coreutils or the path and nothing works) don't forget that busybox provides simple versions of most coreutils. So this works

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busybox ls

See "man busybox" for all the applets provided in this useful package. It even includes some networking stuff like ifconfig, ip, and ping.

[wuxmedia]

@ gekko, yes bad copypasta 8(
thanks Pids, more eyeopeners, as usual 8)
so, theoretically, perhaps not very practically, the busybox package could be used instead of coreutils?

[pidsley]

so, theoretically, perhaps not very practically, the busybox package could be used instead of coreutils?

Yes. If you look at "man busybox" you can see the large list of what is provided, and some tips for how to use the package instead of coreutils. You can either alias everything or use symbolic links from the commands to busybox. In fact, if you look at /bin/ash on your Debian system, you will probably see that it is a symlink to busybox.

This could come in handy if, for example, you forgot to install the "iproute" package and find that you need the "ip" command to set up your network so you can install the iproute package. You can use "busybox ip" instead.

Maybe one of these days I will set up a system without coreutils. I could just remove them from the system I already have that uses busybox as init.

[wuxmedia]

you're getting me excited Pids, because my addled brain has understood your clear description.
Good to see Oppenheimer back too. I bet you look like him too. 8)

[GekkoP]

Interesting stuff, pidsley, as usual. I had a look at busybox but never tried using it instead of coreutils.

[rhowaldt]

@pidsley: thanks for that. i just found out where the problem was. this was in my ~/.bashrc:

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alias ls="ls -F --color --group-directories-first"

changed it to

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alias ls="ls -F --color="auto" --group-directories-first"

and indeed that fixed it. nice 'auto' :)

[GekkoP]

Cleaning.

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find ~/ -name "*~" -exec rm -i {} \;

or

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find ~/ -name ".*~" -exec rm -i {} \;

[pidsley]

"filename: syntax error line 27"

print just line 27:

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sed -n 27p filename

print lines 26 through 28:

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head -28 filename | tail -3

[DebianJoe]

Keeping with the "line numbering" theme, let's say I want to find the line numbers of a regex in a file:

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grep -on "^static" file.c

spits out a list of every line number in file.c that starts with the word 'static'. Removing the 'o' switch, provides the full line text along with the numbers.

[johnraff]

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find | cut -c 3- | env -i egrep '\.(mpc|mp4|mp3|flac)$' > mp3.txt

Yeah I couldn't get regex to play nice in find -shock!

Hmm... felt obliged to come to find's defence... how about:

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find . -iregex '.*\.\(mpc\|mp4\|mp3\|flac\)$' -printf '%P\n' > mp3.txt

Have to escape the ( and | but saves some pipes.

[wuxmedia]

Thanks - you are an honourable man John. 8)

[xaos52]

You think grep is fast?
Try package 'silversearcher-ag' with command 'ag' and think again....

[GekkoP]

^ never heard of it, thanks