Commands by paweljasinski (1)

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pretend to be busy in office to enjoy a cup of coffee
combination of several of the above

Clean swap area after using a memory hogging application
When you run a memory intensive application (VirtualBox, large java application, etc) swap area is used as soon as memory becomes insufficient. After you close the program, the data in swap is not put back on memory and that decreases the responsiveness. Swapoff disables the swap area and forces system to put swap data be placed in memory. Since running without a swap area might be detrimental, swapon should be used to activate swap again. Both swapoff and swapon require root privileges.

kill all processes using a directory/file/etc
This command will kill all processes using a directory. It's quick and dirty. One may also use a -9 with kill in case regular kill doesn't work. This is useful if one needs to umount a directory.

Convert a date to timestamp
Simple way to get a timestamp from a date

Record audio and video from webcam using mencoder
Record audio to MP3 stream and video to MPEG-4 stream from webcam to AVI file using mencoder. Gives floating point exception in some mencoder versions.

Send a backup job to a remote tape drive on another machine over SSH
I use this all the time for taking manual backups of stuff i want to keep but not important enough to backup regularly.

Sort IPV4 ip addresses

Print names of all video files encoded with h264

kills rapidly spawning processes that spawn faster than you can repeat the killall command
if you dont want to alias also then you can do killall rapidly_spawning_process ; !! ; !! ; !!

Mapreduce style processing
parallel can be installed on your central node and can be used to run a command multiple times. In this example, multiple ssh connections are used to run commands. (-j is the number of jobs to run at the same time). The result can then be piped to commands to perform the "reduce" stage. (sort then uniq in this example). This example assumes "keyless ssh login" has been set up between the central node and all machines in the cluster. bashreduce may also do what you want.


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