16.22 Comparing Two Directory Trees with dircmp

You have an original directory. You copy the files in it to another directory, edit some of them, and add a few others. Later, you want to know the differences between the two directories. If your system's diff (28.1) has a -r (recursive) option, you can use that. System V has dircmp. The output of dircmp is formatted with pr (43.7); you get 66-line-long pages with headings:

% dircmp a b

Sep 16 09:26 1991  a only and b only Page 1

./foo.tmp                                   ./defs.h
   ...

Sep 16 09:26 1991  Comparison of a b Page 1

directory   .
same        ./Makefile
directory   ./data
same        ./data/test1
same        ./data/test2
   ...

different   ./pqp.help
same        ./pqs.help
   ...

In the a only and b only listing, files only in the first directory are in the first column and files only in the second directory are in the second column. The Comparison of a b listing compares files that are in both directories. The comparison is recursive - if there are any subdirectories, dircmp checks those, too.

The dircmp -s option stops the "identical file" messages. Use -d to run diff on files that are different; dircmp prints a new page for each diff it runs:

% dircmp -d -s a b
Sep 16 09:35 1991  a only and b only Page 1
   ...
Sep 16 09:35 1991  Comparison of a b Page 1
   ...
Sep 16 09:35 1991  diff of ./pqp.help in a and b Page 1

3c3,4
< -#    "Only this printer"... 'pqp -3' would print on #3.
--
> -#    "Only this printer"... 'pqp -3' would print only on #3;
>       other printer queues will be held.
   ...

The designers assumed you'd want to send the output to a printer. I usually read it on my screen with the less (25.4) pager and its -s option, which squeezes out the multiple blank lines. If you don't have less or more -s, try piping the output through cat -s (25.10) or a sed filter (34.18).