Example 2: Appending “acme.com” to every email address

Match string: \s*(\S*)

Replacement string: $1@acme.com

Input data: fred, jim

Output data: fred@acme.com, jim@acme.com

The string \s* removes any whitespace at the start of the matching string, and (\S*) matches against the remaining non-whitespace characters. The parentheses allow you to reference this matching string as parameter 1 ($1).

In the replacement string, $1 contains the text matched by \S*, and then acme.com is appended to that text.