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A nice command for summarising repeated information

kill some pids without specific pid
pgrep, pkill - look up or signal processes based on name and other attributes

df output, sorted by Use% and correctly maintaining header row
Show disk space info, grepping out the uninteresting ones beginning with ^none while we're at it. The main point of this submission is the way it maintains the header row with the command grouping, by removing it from the pipeline before it gets fed into the sort command. (I'm surprised sort doesn't have an option to skip a header row, actually..) It took me a while to work out how to do this, I thought of it as I was drifting off to sleep last night!

Create the four oauth keys required for a Twitter stream feed
Twitter stream feeds now require authentication. This command is the FIRST in a set of five commands you'll need to get Twitter authorization for your final Twitter command. *** IMPORTANT *** Before you start, you have to get some authorization info for your "app" from Twitter. Carefully follow the instructions below: Go to dev.twitter.com/apps and choose "Create a new application". Fill in the form. You can pick any name for your app. After submitting, click on "Create my access token". Keep the resulting page open, as you'll need information from it below. If you closed the page, or want to get back to it in the future, just go to dev.twitter.com/apps Now customize FIVE THINGS on the command line as follows: 1. Replace the string "Consumer key" by copying & pasting your custom consumer key from the Twitter apps page. 2. Replace the string "Consumer secret" by copying & pasting your consumer secret from the Twitter apps page. 3. Replace the string "Access token" by copying & pasting your access token from the Twitter apps page. 4. Replace string "Access token secret" by copying & pasting your own token secret from the Twitter apps page. 5. Replace the string 19258798 with the Twitter UserID NUMBER (this is **NOT** the normal Twitter NAME of the user you want the tweet feed from. If you don't know the UserID number, head over to www.idfromuser.com and type in the user's regular Twitter name. The site will return their Twitter UserID number to you. 19258798 is the Twitter UserID for commandlinefu, so if you don't change that, you'll receive commandlinefu tweets, uhm... on the commandline :) Congratulations! You're done creating all the keys! Environment variables k1, k2, k3, and k4 now hold the four Twitter keys you will need for your next step. The variables should really have been named better, e.g. "Consumer_key", but in later commands the 256-character limit forced me to use short, unclear names here. Just remember k stands for "key". Again, remember, you can always review your requested Twitter keys at dev.twitter.com/apps. Our command line also creates four additional environment variables that are needed in the oauth process: "once", "ts", "hmac" and "id". "once" is a random number used only once that is part of the oauth procedure. HMAC is the actual key that will be used later for signing the base string. "ts" is a timestamp in the Posix time format. The last variable (id) is the user id number of the Twitter user you want to get feeds from. Note that id is ***NOT*** the twitter name, if you didn't know that, see www.idfromuser.com If you want to learn more about oauth authentication, visit oauth.net and/or go to dev.twitter.com/apps, click on any of your apps and then click on "Oauth tool" Now go look at my next command, i.e. step2, to see what happens next to these eight variables.

Show a random oneliner from commandlinefu.com
This will parse a random command json entry from http://commandlinefu.com A must have in your .bash_profile to learn new shell goodies at login!!!

geoip information
Show external IP and geolocation information. Primary feature is the use of tee to echo IP _and_ send to geoiplookup command...Use IP as input for as many commands as you want with more >( [command] ) Thanks to http://www.commandlinefu.com/commands/view/6334/ Requires MaxMind DB and geoiplookup tool. Sample output has IP obfuscated on first line, lines 2-4 from having MaxMind Country && MaxMind City DBs installed

list block devices
Shows all block devices in a tree with descruptions of what they are.

File rotation without rename command
Rotates log files with "gz"-extension in a directory for 7 days and enumerates the number in file name. i.e.: logfile.1.gz > logfile.2.gz I needed this line due to the limitations on AIX Unix systems which do not ship with the rename command.

ROT13 using the tr command

Show directories in the PATH, one per line
This version uses Pipes, but is easier for the common user to grasp... instead of using sed or some other more complicated method, it uses the tr command


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