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Category Archives: Command line tools

Visualizing Git diffs in Meld.

by Valeriu Paloş on March 7, 2013

Here’s a quick way of configuring your (Linux-based) Git installation to use the excellent Meld program by default for displaying/editing the outputs of the git diff and git merge commands (e.g. git diff «filename»). Install Meld …if you haven’t already (note that we assume Git to be present): # on Debian-based distros (ymmv) sudo apt-get […]

Command-line option parser in JavaScript.

by Valeriu Paloş on May 20, 2011

Here’s a small but very effective command-line option parser written in JavaScript (uses NodeJs). You can get the up-to-date source code at http://gist.github.com/982499. I wrote this because I needed it for a project and I did not think it was worth it to install some npm package just for this. The comment should explain most […]

URI parsing using Bash built-in features

by Valeriu Paloş on February 3, 2010

A bit of background A while ago I posted an article describing how one could parse complete URIs in Bash using the sed program. Since then, I have realized that there is a better way to do it, a much better way: via Bash built-in pattern matching!  Here are some benefits of this improvement: It […]

Recursive chmod distinguishing files from folders

by Valeriu Paloş on December 16, 2009

Version 3 An even better method is: find “$target” -type f -exec chmod -c “$mode_files” {} \; \ -or -type d -exec chmod -c “$mode_dir” {} \; A true one-liner! 😀 Version 2 A better method is this: find “$target” -type f -exec chmod -c “$mode_files” {} \; find “$target” -type d -exec chmod -c […]

Bash URI parser using SED

by Valeriu Paloş on November 16, 2009

Warning! This version is now obsolete! Check out the new and improved version (using only Bash built-ins) here! Here is a command-line (bash) script that uses sed to split the segments of an URI into usable variables. It also validates the given URI since malformed strings produce the text “ERROR” which can be handled accordingly: […]

Recursive file/directory change-detection

by Valeriu Paloş on November 6, 2009

Disclaimer This article explores a way in which an approximate “fingerprint” of a file tree can be created! If all you want is to detect file changes a much more appropriate method would be to use inotify/incron. Version 2 (update) Another, much faster method would be to use ls -lR to browse over the filesystem. […]

Detect number of CPUs on a machine

by Valeriu Paloş on November 6, 2009

UPDATE: Steven pointed out (very nicely) that there’s no need for cat in this picture, grep would do just fine on its own. So, thanks Steven! Detect how many CPU cores are present on the running machine: grep -c processor /proc/cpuinfo This can be very useful when writing multi-threaded programs to properly match the number […]