core dump checking script.

2010-04-11 2 min read Bash Linux Solaris

I was testing a program which crashing every now and then. It is very difficult in such scenarios to keep looking for the <a class="zem_slink" title="Core dump" rel="wikipedia" href="http://en.wikipedia.org/wiki/Core_dump">core file or keep checking for the running process. So I wrote this simple script that can check for core file in the particular path and keep running until it finds one. You can hack this script to send a mail once the core is found. This is a very simple script. And this should work on solaris too..

Bash completion error — quote_readline.

2010-04-11 1 min read Bash

There is a problem with bash completion with quote_readline that causes the completion to fail. The problem is fixed in the bash completion package but there are still some other programs which are using the problematic code. Here is a way to find and resolve it.

First find the problematic program, most likely the recent one after which you started having the problems. Once that is found, find the file containing the definition of the function ”_filedirs()”. Now, delete this file and create a symbolic link to the bash_completion file in the /etc directory. If this file is not present then you need to install the bashcompletion package.

Advanced Sed Substitution Examples

2010-04-11 1 min read Bash Linux

This article is part of the on-going Unix Sed Tips and Tricks series. In our previous sed articles we learned — sed printing, sed deletion, sed substitute , sed file write, and sed multiple commands. In this article, let us review some interesting workarounds with the “s” substitute command in sed with several practical examples. I. […]

Read More: <a href="http://www.thegeekstuff.com/2009/10/unix-sed-tutorial-advanced-sed-substitution-examples/">Unix Sed Tutorial: Advanced Sed Substitution Examples

URL: <a href="http://feedproxy.google.com/~r/TheGeekStuff/~3/uN-cE6UOvfA/">http://feedproxy.google.com/~r/TheGeekStuff/~3/uN-cE6UOvfA/<h6 class="zemanta-related-title" style="font-size: 1em;">Related articles by Zemanta <ul class="zemanta-article-ul"> <li class="zemanta-article-ul-li"><a href="http://www.slumpedoverkeyboarddead.com/2009/08/06/vim-video-tutorial/">VIM video tutorial (slumpedoverkeyboarddead.com) <li class="zemanta-article-ul-li"><a href="http://www.slumpedoverkeyboarddead.com/2009/08/22/turn-vim-or-emacs-into-and-ide-with-exuberant-ctags/">Turn Vim or Emacs Into and IDE With Exuberant-Ctags (slumpedoverkeyboarddead.com) <div class="zemanta-pixie" style="margin-top: 10px; height: 15px;"><a class="zemanta-pixie-a" title="Reblog this post [with Zemanta]" href="http://reblog.zemanta.com/zemified/0d68ebaf-6fc5-419a-a31c-7d31bc55ab3f/"><img class="zemanta-pixie-img" style="border: medium none; float: right;" src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/reblog_e8.png" alt="Reblog this post [with Zemanta]" /><span class="zem-script more-related pretty-attribution">

PuTTY export client display on login for opening X application and terminal.

2010-04-11 1 min read Bash Linux

export DISPLAY=$(echo $SSH_CLIENT |awk '{print $1”:0.0”}’)

Explanation:

SSH_CLIENT contains the IP and the port of the client machine. So we need to export (Client IP):0.0 for the display on the client machine. If the above is put in .bashrc or .bash_profile or .profile, then the DISPLAY variable will be set based on the client machine.

Detecting URLs in a Block of Text

2010-03-31 4 min read Bash

Jan Goyvaerts on <a href="http://www.regex-guru.info/2008/11/detecting-urls-in-a-block-of-text/" target="_blank">Detecting URLs in a Block of Text

In his blog post <a href="http://www.codinghorror.com/blog/archives/001181.html">The Problem with URLs points out some of the issues with trying to detect URLs in a larger body of text using a regular expression.

The short answer is that it can’t be done. Pretty much any character is valid in URLs. The very simplistic <span class="regex">\bhttp://\S+ not only fails to differentiate between punctuation that’s part of the URL, and punctuation used to quote the URL. It also fails to match URLs with spaces in them. Yes, spaces are valid in URLs, and I’ve encountered quite a few web sites that use them over the years. It also forgets other protocols, such as https.

Search & replace with find & ed

2010-03-28 0 min read Bash Learning Linux

$\"Computer$: Image via Wikipedia

function sr() {

declare pattern replacement name usage
declare -i pvar=0 rvar=0 tvar=0

usage='usage: sr [-t ] [-n name] [-p pattern] [-r replacement] [– ] [dir1 dir2 …]'

# cf. <a href="http://bsdpants.blogspot.com/2007/02/option-ize-your-shell-scripts.html">http://bsdpants.blogspot.com/2007/02/option-ize-your-shell-scripts.html

while [[ "${1:0:1}" == '-' ]] ; do

[[ "${1}" == '–' ]] && { shift; break; } # – marks end of options

Recursive Regular Expressions

2010-03-24 2 min read Bash Fedora Linux

<img src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/yo-dawg-regex.jpg" alt="Yo dawg, I heard you liked regular expressions, so I put a regex in your regex so you can match while you match!" align="bottom" /> The <a class="zem_slink freebase/en/regular_expression" title="Regular expression" rel="wikipedia" href="http://en.wikipedia.org/wiki/Regular_expression">regular expressions we use in our daily lives are actually not that “regular.” Most of the languages support some kind of extended regular expressions that are computationally more powerful than the “<a href="http://en.wikipedia.org/wiki/Regular_expression">regular” regular expressions as defined by the <a href="http://en.wikipedia.org/wiki/Formal_language">formal language theory.