two sorted files line by line.
comm [-123i] file1 file2
-1 Suppress printing of column 1
-2 Suppress printing of column 2
-3 Suppress printing of column 3
-i Case insensitive comparison of lines
comm utility reads file1 and
file2, which should
be sorted lexically, and produces three text columns as output:
Lines only in file1; Lines only in file2; Lines in both files.
printing of a column is suppressed, the output will be padded with TAB
column will have a number of tab characters prepended to it equal to the number
of lower numbered columns that are being printed. For example, if column number
two is being suppressed, lines printed in column number one will not have any
tabs preceding them, and lines printed in column number three will have one.
comm utility assumes that the files are lexically sorted; all characters
participate in line comparisons. The filename '-' means
Collation sorting: the LANG, LC_ALL, LC_COLLATE, and LC_CTYPE environment
variables affect the execution of comm