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Use xdg-open to avoid hard coding browser commands
I rarely use the system menu to start applications. I use keyboard shortcuts instead. Keyboard shortcuts are convenient time savers. To configure the shortcuts I use gconf-editor or CompizConfig Settings Manager (if I have Compiz turned on). Lately I've been using Chromium as my browser. Since Chromium is under heavy development it occasionally becomes unusable and I have to switch back to Firefox. I was hard-coding the browser command in my keyboard shortcuts. This became problematic with frequent browser hopping. I now use the xdg-open command when defining my keyboard shortcuts. xdg-open opens a file or URL in the user's preferred application. In the metacity keybinging_commands I have xdg-open http://gmail.com where I used to have firefox http://gmail.com. Now when switching browsers I don't have to update each keyboard binding command I just change my default browser in Ubuntu by clicking through the menu: System / Preferences / Preferred Applications / Web Browser. xdg-open is more convenient for this browser hopper.

Find out how old a web page is
I used to use the Firefox "View page info" feature a lot to determine how stale the web page I was looking at was. Now that I use mostly Chrome I miss that feature, so here is a command line alternative using wget. The -S says to display the server response, the --spider says to not download any files/pages, just fetch the header. The output goes to stderr, so to grep it you use 2>&1 to combine the stderr stream with stdout, the pipe that to grep for Last-Modified. You can use curl instead if you have it installed, like this: $ curl --head -s http://osswin.sourceforge.net | grep Mod

Regnerate Exif thumbnail.
Regnerate Exif thumbnail.

c_rehash replacement
When you don't have c_rehash handy. Really simple - if you have a .pem file that doesn't really contain a x509 cert (let's say, newreq.pem), it will create a link, simply called '.0', pointing to that file.

Update twitter with curl
Same as below, but no quotes are necessary when twitting more than one word

Listing directory content of a directory with a lot of entries
Ever wanted to get the directory content with 'ls' or 'find' and had to wait minutes until something was printed? Perl to the rescue. The one-liner above(redirected to a file) took less than five seconds to run in a directory with more man 2 million files. One can adapt it to e.g. delete files that match a certain pattern.

Extract audio track from a video file using mencoder
Extracts an MP3 encoded audio stream from an input video file.

locate a filename, make sure it exists and display it with full details
use the locate command to find files on the system and verify they exist (-e) then display each one in full details.

Check if x86 Solaris based system is 32bit or 64bit
This is likely only valid on Solaris based systems. Unfortunately a lot of the more universal techniques for determining if a system is 32bit or 64bit on x86 solaris fail to give much more information than "i86pc"

Encode a string using ROT47
This command will encode a string using the ROT47 cipher.


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