Question

I would like to edit a file containing a set of email ids such that all the domain names become generic.

Example,
[e-mail],
[e-mail],
[e-mail]

to
[e-mail],
[e-mail],
[e-mail]

I used the following sed command,

sed '/@/,/.com/ s//generic/' filename.txt

here the sed replaces ‘@’ with ‘generic and .com with ‘generic’ and not the content in between @ and .com

Answer 1

Use

sed 's/@[^,]*/@generic.com/'

This will replace everything after the “@” until the first comma with generic.com, thereby fixing the domain, and leaving the ending comma in tact.

Since you seem to have some confusion, ranges (/regex/,/otherregex/) select a number of lines, not positions within a line.