We need to get the line: starting with "["; containing "5060"; containing "conv".
Example usage:
cat gateway.cfg | grep '^\[\|5060\|conv'
or
cat gateway.cfg | egrep '^\[|5060|conv'
If we need to get lines with one of our patterns - use grep -e option. Example:
grep -e "test" -e "second pattern" -e "third pattern"