The FreeBSD version (1.3.2.6 1999/09/05) has over the NetBSD version
(1.16 1998/12/19):
 -l flag (list database)
 trailing \n on some syslog messages
 strerror(errno) instead of the %m macro in syslog messages
 isdelim() used in nsearch()

The OpenBSD version (1.12 1999/06/03) has over the NetBSD version:
 correctly initialises a zero-lenght vacation.db
 no "vacation: " prefix in syslog messages
 uses Return-Path instead of From_, if present
 $SUBJECT substitution in the message

The old debian version has over the FreeBSD version:
 discard_exit()

The sendmail version (8.68.4.3 2000/04/27) has over the NetBSD version:
 -fmstxz
 annoying license

Things in the sourceforge version:
 $FROM substituion
 has -j
 does stupid things with the envelope sender in readheaders(), mistaking
  it for a bang path
 wastes time passing the -F argument to sendmail
 interval is set with -t, but can only be specified in weeks
 installation procedure

 The -r flag of the sourceforge version is a very, very dangerous thing
 because automatically generated replies MUST go to the envelope sender.
 This version also ignores the From header.

Things in the AIX 4.3 version:
 /usr/share/lib/vacation.def
 interval set with -f (like -t in solaris, with unit)

Things in the DU version:
 /usr/share/lib/vacation.def
 interval can't be set (1 week)

Things in the HP-UX 10.20 version:
 /usr/share/lib/vacation.def
 interval can't be set (1 week)

Things in the IRIX version (a very old BSD port):
 interval set with -r (in days?)

Things in the Solaris version:
 /etc/mail/vacation.def (used in the automatical installation process)
 interval set with -t (with unit)
 installation procedure

http://www.FreeBSD.org/cgi/cvsweb.cgi/src/usr.bin/vacation/?cvsroot=freebsd
http://www.FreeBSD.org/cgi/cvsweb.cgi/basesrc/usr.bin/vacation/?cvsroot=netbsd
http://www.FreeBSD.org/cgi/cvsweb.cgi/src/usr.bin/vacation/?cvsroot=openbsd

