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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.

Chrome sucks

burn an ISO image to writable CD
Does life get much easier? Read up about wodim for an understanding of its origins in relation to the older `cdrecord` utility

live ssh network throughput test
connects to host via ssh and displays the live transfer speed, directing all transferred data to /dev/null needs pv installed Debian: 'apt-get install pv' Fedora: 'yum install pv' (may need the 'extras' repository enabled)

backup a directory in a timestamped tar.gz
creates a tar.gz with a name like: backup20090410_173053.tar.gz of a given directory. this file was made 10 April 2009 at 5:30:53pm see date's man page to customize the timestamp format

bulk rename files with sed, one-liner
Far from my favorite, but works in sh and with an old sed that doesn't support '-E'

check open ports without netstat or lsof

Safe Delete
remove file that has sensitive info safely. Overwrites it 33 times with zeros

convert ascii string to hex
You can use "decode()" in a similar manner: $ python -c 'print "68656c6c6f".decode("hex")'

Install pip with Proxy
Installs pip packages defining a proxy


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