sed command syntax with example

[Guest_imported]

I want to know the (sed) command syntax and the usage. suppose I have a file like this

file content
-------------------
abc
def
xxx
yyy

I want to change the particular word say 'xxx' to 'www' without doing in vi editor, I think I can use the sed command right, please send me the syntax with an ex.
(mail me on bsmurugavel@yahoo.com)

 

[Annihilannic]

sed syntax,

Try this:

[tt] sed 's/xxx/

http://www/g'

< file.txt > file.out[/tt]

The command string means to substitute all occurrences of 'xxx' with '

http://www'.

The 'g' means global, which makes it replace more than one occurrence on each line (if present).

Annihilannic.