You probably could use process substitution to get rid of the temp file: comm -12 Whitelist <(ag MyString | awk -F: '{print $1}' | sort | uniq) > Output The

You probably could use process substitution to get rid of the temp file: comm -12 Whitelist <(ag MyString | awk -F: '{print $1}' | sort | uniq) > Output Then you could use unique flag of sort: comm -12 Whitelist <(ag MyString | awk -F: '{print $1}' | sort -u) > Output Also ag can list only matching files (getting rid of awk and unique): comm -12 Whitelist <(ag -l MyString | sort) > Output