Commands by tuxifier (2)

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Empty a file
Immediately make a file empty. This even works if the file is still being written to. Great for cleaning up huge log files!

Find the package that installed a command

Print a row of characters across the terminal
shorter than alternative

A command line calculator in Perl
Once I wrote a command line calculator program in C, then I found this... and added to it a bit. For ease of use I normally use this in a tiny Perl program (which I call pc for 'Perl Calculator') #!/usr/bin/perl -w die "Usage: $0 MATHS\n" unless(@ARGV);for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g}; print eval(join('',@ARGV)),$/; It handles square roots, power, modulus: $ pc 1+2 (1 plus 2) 3 $ pc 3x4 (3 times 4) 12 $ pc 5^6 (5 to the power of 6) 15625 $ pc v 49 ( square root of 49 ) 7 $ pc 12/3 (12 divided by 3) 4 $ pc 19%4 (19 modulus 4) 3 (you can string maths together too) $ pc 10 x 10 x 10 1000 $ pc 10 + 10 + 10 / 2 25 $ pc 7 x v49 49

Go up multiple levels of directories quickly and easily.
Change to your taste. Much quicker than having to add 'cd' every time. Add it to your .bashrc or .bash_profile.

Resolution of a image
You can use the -format switch to get the size of the image. Replace "logo:" with your image.

Display the output of a command from the first line until the first instance of a regular expression.
If BREs can be used, this sed version will also get the job done.

Mount a disk image (dmg) file in Mac OSX
To unmount, replace "attach" with "eject"

Take a screenshot every 2 seconds
Take a screenshot every 2 seconds and save it as a png file

Show current working directory of a process


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