Question

I want to search for a string and replace it with another string recursively under a directory.
for example:
I want to search for a string

"var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");"

and replace it with

var _gaq = _gaq || [];_gaq.push(['_setAccount', 'UA-7044592-1']);_gaq.push(['_setDomainName', 'news4u.com']);_gaq.push(['_trackPageview']);

How to achieve it ?

Answer 1

Use find to find all files, and xargs to run sed to modify them:

find dir -type f | xargs sed -i.bak 's#from#to#'

that will find all files under dir and replace from with to, backing up the original files with the extension “.bak”

N.B. from is a basic regular expression, so you will need to escape any BRE metacharacters in the string you are searching for. It would be a good idea to test the sed command on a single file to get it working:

sed 's#from#to#' file > test.out

That will do the replacements to file but instead of modifying file it will write the output to test.out so you can check the results.