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Tricky implementation of two-dimensional array in Bash.
Since Bash doesn't support two-dimensional arrays, you can limit your columns length by some big enough constant value ( in this example 100 ) and then index the array with i and j, or maybe write your own get() and set() methods to index the array properly like I implemented for example ( see Sample output ). For example for i=0 and j=0...99 you'll pick up one of 100 elements in the range [0,99] in the one-dimensional array. For i=1 and j=0...99 you'll pick up one of 100 elements in the range [100,199]. And so on. Be careful when using this, and remember that in fact you are always using one-dimensional array.

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"

Benchmark SQL Query
Benchmark a SQL query against MySQL Server. The example runs the query 10 times, and you get the average runtime in the output. To ensure that the query does not get cached, use `RESET QUERY CACHE;` on top in the query file.

%s across multiple files with Vim
src: http://www.ibrahim-ahmed.com/2008/01/find-and-replace-in-multiple-files-in.html

cat a bunch of small files with file indication
If you have a bunch of small files that you want to cat to read, you can cat each alone (boring); do a cat *, and you won't see what line is for what file, or do a grep . *. "." will match any string and grep in multifile mode will place a $filename: before each matched line. It works recursively too!!

concatenate avi files
concatenates avi files

Generate 10 pronunciable passwords
A great password generation tool. http://www.adel.nursat.kz/apg/

Colorized grep in less
Get your colorized grep output in less(1). This involves two things: forcing grep to output colors even though it's not going to a terminal and telling less to handle those properly.

get you public ip address
Relies on ifconfig.me functioning. It's about as easy as it gets, and memorable to old geeks too.

Getting a domain from url, ex: very nice to get url from squid access.log


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