Any number of existing mailboxes may be given as arguments. If the mailboxes are in the locations where Mail.app would look for them the pathname and the `.mbox' extension may be dropped.
Listmail accepts two options. If it is invoked with -n it will list the table_of_contents immediately even if the mailbox is locked by another program. There is no danger of data corruption as listmail never writes any data. If the -n option is not given listmail will wait for the mailbox to become available just like the other programs in this suite. The option -v causes listmail to be more verbose about what it does. The opposite is achieved with the option -t. If it is set listmail will only spew the message count to the standard output.
The task was made considerably easier by Chris Paris <cap+@cmu.edu> decoding of the Mail.app transmission and storage formats.
Tom Hageman <mailapp-utilities@basil.icce.rug.nl> is the current maintainer.