How to change a string in a text file on a Linux server

So, you want an easy to to replace text in files, even multiple files, on a linux machine, from the command line.
How? - You ask? Easy.

Let me show you.
Let’s say you want to replace all instances of “John” with “Pete” in a file, called resume.txt
In a bash shell, run the following:
Code:

PHP Code:

PHP Code:
 replace John Pete — resume.txt 
Now, how about replacing all instance of “/home/” with “/home2/”? in all files located in /etc/? (let’s say you have moved the home folder)
Code:

PHP Code:
PHP Code:
 replace /home/ /home2/ — /etc/* 
Or, you want to update your DNS servers quickly, after moving your servers to a new domain. The old domain was mydomain.com & the new domain is ourdomain.com
Code:

PHP Code:

PHP Code:
      replace mydomain newdomain — /var/named/*.db