Question

The following command works as expected and changes the username to abc

sed -e 's/username=company_user/username=abc/' Service.properties 

But if the username is something different other than ‘company_user’ it will fail for obvious reasons.
How do I use wildcards here?

Answer 1

It depends on what is a valid username, but here’s a start:

sed 's/username=[a-z0-9_]+/username=abc/i' Service.properties

This will replace any username consisting of upper or lower case letters (note the i at the end, which makes the pattern case-insensitive), numbers and/or underscores with “abc”. If you need to add other characters, just add them within the [].