Linux Shell Scripting Cookbook - Third Edition

How to do it...

The sed command can replace occurrences of a pattern with another string. The pattern can be a simple string or a regular expression:

    $ sed 's/pattern/replace_string/' file 

Alternatively, sed can read from stdin:

    $ cat file | sed 's/pattern/replace_string/'

If you use the vi editor, you will notice that the command to replace the text is very similar to the one discussed here. By default, sed only prints the substituted text, allowing it to be used in a pipe.

    $ cat /etc/passwd | cut -d : -f1,3 | sed 's/:/ - UID: /'
    root - UID: 0
    bin - UID: 1
    ...

1. The -I option will cause sed to replace the original file with the modified data:

        $ sed -i 's/text/replace/' file

2. The previous example replaces the first occurrence ...