What is the correct way to use grep/awk/sed?

Question

linux

There is a file in which the software writes data in this form:
string.1 <character tab> OK
string.2 <character tab> OK
string.3 <character tab> OK
There is a script that should parse data from another source using the contents the above file via grep -f filename . The problem is that data from the source comes in the form of just string.1, string.2 and string.3 without "OK", i.e. are not included in the template. Now a crutch is working there, which reads the first file, cuts out everything "OK" from it, saves the result to an intermediate file, which is already slipped into the script. But I believe that you can make the whole operation less crutch, somehow cutting out this "OK" on the fly.
What is the best way to do this?

Answer 1

cut -f1 -d$'\t'
awk '{ print $1 }'