On 4/6/21 4:24 AM, Paul Eggert wrote: > grep -Fvf file2 file1 I started with that, too, but it is problematic because: a) it doesn't do a whole-word search ... and 'grep -w' seems not to be portable, b) it doesn't limit the matching on the key field. And messing with regular expressions seems to be fragile as well, because the key field may contain problematic characters.
Have a nice day, Berny