Последнее сообщение в mcabber

# External command for events
# You can specify a script or process to be launched when an event occurs.
#
# If 'event_log_files' is set, a file is created and contains the body of
# the message (incoming messages only); the file name is the last parameter.
# If you enable this, you can specify the directory mcabber will use to
# create these messages with the 'event_log_dir' variable (default is the
# system temp dir, or MCABBERTMPDIR environment variable).  Please note
# that mcabber won't delete these files, it's your script's job.
#
# The command is called the following way:
#   $events_command MSG IN jabber@id [file] (when receiving a message)
#   $events_command MSG OUT jabber@id       (when sending a message)
#   $events_command MSG MUC room_id [file]  (when receiving a MUC message)
#   $events_command STATUS X jabber@id      (new buddy status is X)
# See sample script in contrib/ directory.
#
#set events_command = ~/myscript.sh
#
#set event_log_files = 0
#set event_log_dir = ~/.mcabber/event_files

Подчерпнуть информации можно еще здесь http://www.kernelcrash.com/blog/jabber-messages-in-your-dwm-status-bar/2007/11/23/