Commands tagged system update (2)

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Run a command multiple times with different subcommands
it's nice to be able to use the command `ls program.{h,c,cpp}`. This expands to `ls program.h program.c program.cpp`. Note: This is a text expansion, not a shell wildcard type expansion that looks at matching file names to calculate the expansion. More details at http://www.linuxjournal.com/content/bash-brace-expansion I often run multiple commands (like apt-get) one after the other with different subcommands. Just for fun this wraps the whole thing into a single line that uses brace expansion.

Generate soothing noise
Substitute 'brown' with 'pink' or 'white' according to your taste. I put this on my headphones when I'm working in an "open concept" office, where there are always three to five conversations going in earshot, or if I'm working somewhere it is "rude" of me to tell a person to turn off their cubicle radio.

Print the IPv4 address of a given interface

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

Convert spaces in file names to underscores

Count the words in any OpenOffice document (including Impress presentations)
OpenOffice, LibreOffice and OO Impress wordcount

Create executable, automountable filesystem in a file, with password!
This is just a proof of concept: A FILE WHICH CAN AUTOMOUNT ITSELF through a SIMPLY ENCODED script. It takes advantage of the OFFSET option of mount, and uses it as a password (see that 9191? just change it to something similar, around 9k). It works fine, mounts, gets modified, updated, and can be moved by just copying it. USAGE: SEE SAMPLE OUTPUT The file is composed of three parts: a) The legible script (about 242 bytes) b) A random text fill to reach the OFFSET size (equals PASSWORD minus 242) c) The actual filesystem Logically, (a)+(b) = PASSWORD, that means OFFSET, and mount uses that option. PLEASE NOTE: THIS IS NOT AN ENCRYPTED FILESYSTEM. To improve it, it can be mounted with a better encryption script and used with encfs or cryptfs. The idea was just to test the concept... with one line :) It applies the original idea of http://www.commandlinefu.com/commands/view/7382/command-for-john-cons for encrypting the file. The embedded bash script can be grown, of course, and the offset recalculation goes fine. I have my own version with bash --init-file to startup a bashrc with a well-defined environment, aliases, variables.

Most Commonly Used Grep Options
This is very helpful to place in a shell startup file and will make grep use those options all the time. This example is nice as it won't show those warning messages, skips devices like fifos and pipes, and ignores case by default.

Monitor RAID IO Usage
Shows the IO of the raid sync

Get a list of IP Addresses that have failed to login via SSH
This command shows a sorted list of the IP addresses from which there have been authentication errors via SSH (possible script kiddies trying to gain access to your server), it eliminates duplicates so it's easier to read, but you can remove the "uniq" command at the end, or even do a "uniq -c" to have a count of how many times each IP address shows in the log (the path to the log may vary from system to system)


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