Parsing of the mailstats program's output can be made more program-friendly with the use of the -p command-line switch:

% mailstats -p
938478602 938718475
 0        0          0      247        686        0       0  prog
 3       42         96        2          5        0       0  local
 5      472       1710       10         22        5       0  esmtp
 T      514       1806      259        713        5       0
 C      514        259        5

Here, the first line contains two dates in Unix time(2) format. The first is the date/time the file was created (or zeroed), and the second is the date/time mailstats was run.

The rest of the lines are what you have already seen when mailstats was run without the -p. The M heading and attractive horizontal lines are missing, but the data is the same in both cases.

If the user running the mailstats program has write permission to the statistics file, this -p switch will also cause that file's contents to become zeroed. If the user running the program lacks write permission to the statistics file, that file's contents will not be zeroed. Zeroing and not zeroing are silent. You need to run the mailstats program a second time to discover if the statistics file has been zeroed.

Beginning with V8.12 sendmail, you can use the -P command-line switch (discussed next) to print statistics in program-friendly form, without zeroing the statistics.

Note that the -o switch can combined with the -p switch to produce program-friendly output that excludes the last, human-readable column:

% mailstats -p -o
938478602 938718475
 0        0          0      247        686        0       0
 3       42         96        2          5        0       0
 5      472       1710       10         22        5       0
 T      514       1806      259        713        5       0
 C      514        259        5