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Cycles continuously through a string printing each character with a random delay less than 1 second. First parameter is min, 2nd is max. Example: 1 3 means sleep random .1 to .3. Experiment with different values. The 3rd parameter is the string. The sleep will help with battery life/power consumption.
$ cycle 1 3 $(openssl rand 100 | xxd -p)
Fans of "The Shining" might get a kick out of this:
$ cycle 1 4 ' All work and no play makes Jack a dull boy.'
An advantage is that this doesn't modify remained string at all. One can change {0,1} with {0,n} to drop several columns
Reports all local partitions having more than 90% usage.
Just add it in a crontab and you'll get a mail when a disk is full.
(sending mail to the root user must work for that)
This command creates and burns a gapless audio CD with 99 tracks. Each track is a 30 second sine wave, the first is 1 Hz, the second 2 Hz, and so on, up to 99 Hz. This is useful for testing audio systems (how low can your bass go?) and for creating the constant vibrations needed to make non-Newtonian fluids (like cornstarch and water) crawl around.
Note, this temporarily creates 500MB of .cdda files in the current directory. If you don't use the "rm" at the end of the command, you can burn more disks using
$ cdrdao write cdrdao.toc
Prerequisites: a blank CD-R in /dev/cdrw, sox (http://sox.sourceforge.net/), and cdrdao (http://cdrdao.sourceforge.net/). I'm also assuming a recent version of bash for the brace expansion (which just looks nicer than using seq(1), but isn't necessary).
More info here:
http://nagioswiki.com/wiki/index.php/Autocreating_Nagios_Configuration_with_Nmap_and_Nmap2Nagios.pl
This dumps serial numbers of all the drives but HP warranty check does not say they are valid ...
I put this in a shell script called "svndiff", as it provides a handy decorated "svn diff" output that is colored (which you can't see here) and paged. The -r is required so less doesn't mangle the color codes.
List the commands you have the right to use with sudo.