The HylaFAX Fax Service
Many current Unix operating systems provide some sort of fax support. In this section, we’ll consider the free HylaFAX package, originally written by Sam Leffler while at Silicon Graphics, because it is the most widely used and is available for many different Unix versions. HylaFAX is capable of sending and receiving faxes on the local system, and accepting fax jobs from other hosts on the network. Outgoing faxes are queued as necessary. An interface to electronic mail is also available. The package’s home page is http://www.hylafax.org.
Fax services are provided by three daemons:
The queuing agent, which prepares fax files, and schedules and initiates outgoing fax transmissions.
The fax server daemon, which provides local and remote fax submission support, access control and other management functions.
gettyimplementation which handles incoming faxes.
The package also includes a variety of utilities, many of which we’ll consider here; the corresponding binary files are mainly stored in /usr/local/bin and /usr/local/sbin, although a few are in /var/spool/hylafax/bin (if you use the default installation directories).
Actual fax images are stored in the subdirectories docq (outgoing) and recvq (incoming) under /var/spool/hylafax . Other important subdirectories of this main HylaFAX spooling location are sendq (outgoing job control files), log (contains log files for each fax session), config (modem type definitions), and etc (most HylaFAX ...