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kill some process (same as others) but parsing to a variable
Kills a process matching program. I suggest using $ pgrep -fl program to avoid over-killings Nice the following: kills all bash process owned by guest $ pkill -9 -f bash -u guest

List your MACs address

See how many more processes are allowed, awesome!
There is a limit to how many processes you can run at the same time for each user, especially with web hosts. If the maximum # of processes for your user is 200, then the following sets OPTIMUM_P to 100. $ OPTIMUM_P=$(( (`ulimit -u` - `find /proc -maxdepth 1 \( -user $USER -o -group $GROUPNAME \) -type d|wc -l`) / 2 )) This is very useful in scripts because this is such a fast low-resource-intensive (compared to ps, who, lsof, etc) way to determine how many processes are currently running for whichever user. The number of currently running processes is subtracted from the high limit setup for the account (see limits.conf, pam, initscript). An easy to understand example- this searches the current directory for shell scripts, and runs up to 100 'file' commands at the same time, greatly speeding up the command. $ find . -type f | xargs -P $OPTIMUM_P -iFNAME file FNAME | sed -n '/shell script text/p' I am using it in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html especially for the xargs command. Xargs has a -P option that lets you specify how many processes to run at the same time. For instance if you have 1000 urls in a text file and wanted to download all of them fast with curl, you could download 100 at a time (check ps output on a separate [pt]ty for proof) like this: $ cat url-list.txt | xargs -I '{}' -P $OPTIMUM_P curl -O '{}' I like to do things as fast as possible on my servers. I have several types of servers and hosting environments, some with very restrictive jail shells with 20processes limit, some with 200, some with 8000, so for the jailed shells my xargs -P10 would kill my shell or dump core. Using the above I can set the -P value dynamically, so xargs always works, like this. $ cat url-list.txt | xargs -I '{}' -P $OPTIMUM_P curl -O '{}' If you were building a process-killer (very common for cheap hosting) this would also be handy. Note that if you are only allowed 20 or so processes, you should just use -P1 with xargs.

fork performance test
grabbed from Andrew Aylett post: http://superuser.com/questions/133313/can-i-speed-up-cygwins-fork

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

List only directories, one per line

Remove Thumbs.db files from folders

Quick and dirty convert to flash
This converts any media ffmpeg handles to flash. It would actually convert anything to anything, it's based on the file extension. It doesn't do ANY quality control, sizing, etc, it just does what it thinks is best. I needed an flv for testing, and this spits one out easily.

AES file encryption with openssl
To decrypt: openssl aes-256-cbc -d -in secrets.txt.enc -out secrets.txt.new Reference: http://tombuntu.com/index.php/2007/12/12/simple-file-encryption-with-openssl Optional parameter -a makes output base64 encoded, can be viewed in text editor or pasted in email

Clear mistyped passwords from password prompt
Type ^u at password prompt to clear a mistyped password.


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