Stan Ryckman wrote,
| This seems to work:
| formail -s formail -X 'From ' < mailbox | wc -l
| but due to the number of processes, it's *very* slow.
You don't need the extra formail for each message, as Alan Stebbens has
posted.
formail -X'From ' -s < mailbox | wc -l
will run much faster. Stephen van den Berg has suggested this, and it may be
faster yet because it feeds less text to wc:
formail -I'From x' -zx'From ' < mailbox | wc -l # or | wc -w
And, unlike grep -c '^From ', it won't be fooled by occurrences of "^From "
in the body that are protected by a Content-Length: header.