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regular expressions

WordPress Rename Image URL For a CDN Usage

Recently, we moved all our static assets to a CDN (Content Delivery Network) as described here. However, we have over 8000+ old blog posts and we need to point static images url to our CDN account hosted at http://MyACCOUNT.cloudfront.net/images/ folder. How do I rename all image urls stored in wordpress posts? How do I offload static images to a CDN urls under WordPress?
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I've tons of images, css and javascript hosted at backend server IP 192.168.1.5 and 192.168.1.6. How do I make sure nginx reverse proxy load balancer always send all http_user_agent requests coming from "Mozilla" to server 192.168.1.5 and MSIE to server 192.168.1.6 only?
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How do I determine whether a variable called spath="/srv/www/cyberciti.biz/https" contains a substring called "cyberciti.biz"?
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Regular Expressions In grep

How do I use the Grep command with regular expressions on a Linux and Unix-like operating systems?
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Q. How do I find the text between the strings FOO and BAR inclusive using sed command line option?
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Q. How do I use sed for selective deletion of certain lines? I have text as follows in file:
Line 1
Line 2
WORD1
Line3
Line 4
WORD2
Line5

I would like to delete all lines between WORD1 and WORD2 to produce final output:
Line 1
Line 2
Line5

A. For selective deletion of certain lines sed is the best tool. To print all of file EXCEPT section between WORD1 and WORD2 (2 regular expressions), use
$ sed '/WORD1/,/WORD2/d' input.txt > output.txt

Shell script to remove Javascript code

Here is my small script that reads all *.html files and removes javascript (script download link).

#!/bin/bash
# ALL HTML FILES
FILES="*.html"
# for loop read each file
for f in $FILES
do
INF="$f"
OUTF="$f.out.tmp"
# replace javascript
sed '/<script type="text\/javascript"/,/<\/script>/d' $INF > $OUTF
/bin/cp $OUTF $INF
/bin/rm -f $OUTF
done

Above shell script removes all occurrence of javascript.