Commands by srounce (1)

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Optimal way of deleting huge numbers of files
This command works by rsyncing the target directory (containing the files you want to delete) with an empty directory. The '--delete' switch instructs rsync to remove files that are not present in the source directory. Since there are no files there, all the files will be deleted. I'm not clear on why it's faster than 'find -delete', but it is. Benchmarks here: https://web.archive.org/web/20130929001850/http://linuxnote.net/jianingy/en/linux/a-fast-way-to-remove-huge-number-of-files.html

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Convert files from DOS line endings to UNIX line endings
This method will also convert mac line endings.

Unlock your KDE4.3 session remotely
The unlock command for KDE 4.3 has changed from krunner_lock, this process doesn't exist anymore. So here's the update :-) If qdbus complains about not being able to find X, put a "DISPLAY=:0 " (:0 being your X server display) in front of the command.

Extract audio stream from an AVI file using mencoder
This commands saves the output in the audio directory. The portion ${file/%avi/mp3} uses bash string replacement to replace the avi to mp3 within the ${file} variable.

Apply, in parallel, a bc expression to CSV
Define a function that applies bc, the *nix calculator, with the specified expression to all rows of the input CSV. The first column is mapped to {1}, second one to {2}, and so forth. See sample output for an example. This function uses all available cores thanks to GNU Parallel. Requires GNU Parallel

Remove trailing space in vi

remove files and directories with acces time older than a given date
touch a dummy file with the specified date, then use find with -anewer .

Generate trigonometric/log data easily

Keep one instance of an irc chat client in a screen session
This command attempts to attach to existing irssi session, if one exists, otherwise creates one. I use "irc" because I use different irc clients depending on what system I am working on. Consistency is queen.


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