cd across parallel directories

Here is a simple and fast way to cd across parallel directory.

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      cd ${PWD/test/actual}
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/bash debugger

9.2. A bash Debugger

In this section we’ll develop a very basic debugger for bash.[10] Most debuggers have numerous sophisticated features that help a programmer in dissecting a program, but just about all of them include the ability to step through a running program, stop it at selected places, and examine the values of variables. These simple features are what we will concentrate on providing in our debugger. Specifically, we’ll provide the ability to:

some bash exercise for you

Here is some teaser for you, can you figure out how this works:

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      echo ls<br /> <br /> !!:1-$
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bash regular expressions

Here are some quick links on bash regular expressions, pretty good links to bookmark, if you use, regular expressions in bash regularly. I especially like the tldp link at number 3.

http://www.linuxjournal.com/content/bash-regular-expressions
http://www.ibm.com/developerworks/library/l-bash.html
http://tldp.org/LDP/abs/html/parameter-substitution.html#VARMATCH
http://wellington.pm.org/archive/200005/codegen/index9.htm

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bash math

some quick links :

http://mainstreetanswers.org/bash/math.php
http://www.faqs.org/docs/abs/HTML/mathc.html
http://tldp.org/LDP/abs/html/mathc.html

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shopt causes bash completion to stop working.

Couple of days, I added some scripts to my bash startup and suddenly realized that bash completions stopped working. This is tricky situation in bash to figure out what went wrong. So, I set my foot down to make sure that I find out the culprit. Thus I started with method of elimination. So, I started with nothing in .bashrc and kept adding my stuff in batches, until the said feature was broken. Once that happened I started removing the added ones, one by one, until my completion started working again.

Find all the missing paths in the PATH variable in bash script

Here is a simple script that will list out all the paths in the PATH variable that do not exist.

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      #!/bin/bash -<br /> #===============================================================================<br /> #<br /> #          FILE:  wrong_path.sh<br /> #<br /> #         USAGE:  ./wrong_path.sh<br /> #<br /> #   DESCRIPTION:  Show Directories in the PATH Which does NOT Exist<br /> #<br /> #       OPTIONS:  ---<br /> #  REQUIREMENTS:  ---<br /> #          BUGS:  ---<br /> #         NOTES:  ---<br /> #        AUTHOR:  Amit Agarwal (AKA), amit.agarwal@amit-agarwal.co.in<br /> #       COMPANY:  Individual<br /> #       VERSION:  1.0<br /> #       CREATED:  09/20/2009 09:15:48 AM IST<br /> #      REVISION:  ---<br /> #===============================================================================<br /> <br /> set -o nounset                              # Treat unset variables as an error<br /> <br /> (IFS=:;for p in $PATH; do test -d $p || echo $p; done)
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