.CT 1 files comm - select or reject lines common to two sorted files comm [ -123 ] file1 file2 Comm reads file1 and file2 , which are in lexicographical order, and produces a three column output: lines only in file1 ; lines only in file2 ; and lines in both files. The file name .L - means the standard input.

Flag .LR 1 , .LR 2 , or .LR 3 suppresses printing of the corresponding column.

.EX comm -12 file1 file2

Print lines common to two sorted files. /sys/src/cmd/comm.c sort (1), cmp (1), diff (1), uniq (1)