توضیحاتش رو نگاه کردم :
plog shows you the last few lines of /var/log/ppp.log. If that file doesn’t exist, it shows you the last few lines
of your /var/log/syslog file, but excluding the lines not generated by pppd. This script makes use of the tail(1)
command, so arguments that can be passed to tail(1) can also be passed to plog.
ظاهرا چند تا خط اخر از ppp.log و sys.log رانمایش میده همین و بس
شما هم یه نگاهی بندازید