I have found that using perl expressions "-P" in
conjunction with the "Search Headers" (-H) causes
mboxgrep to select ALL messages from the Mailbox.
Example:
mboxgrep -H -o ./spam.box -P
"Subject:\s+(?:Assertive\s+and\s+strong|Black\s+Jack\,\s+Poker\,\s+Slots\s+\-\s+No\s+Fee\s+to\s+Try\s+It\s+\-\s+Progressive\s+Jack\s+Pots)"
./notspam
Results in spam.box of:
ls -l spam.box
-rw------- 1 larrys users 9249071 2005-10-26
13:30 spam.box
Removing the "-H" flag:
mboxgrep -o ./spam.box -P
"Subject:\s+(?:Assertive\s+and\s+strong|Black\s+Jack\,\s+Poker\,\s+Slots\s+\-\s+No\s+Fee\s+to\s+Try\s+It\s+\-\s+Progressive\s+Jack\s+Pots)"
./notspam
Results in spam.box of:
ls -l spam.box
-rw------- 1 larrys users 25026 2005-10-26
13:32 spam.box
Both ran against the same input mailbox.