Application Packaging Developer's Guide

The sed Class Action Script (/etc/inittab)

!remove
# remove all entries from the table that are associated
# with this package, though not necessarily just
# with this package instance
/^[^:]*:[^:]*:[^:]*:[^#]*#ROBOT$/d
!install
# remove any previous entry added to the table
# for this particular change
/^[^:]*:[^:]*:[^:]*:[^#]*#ROBOT$/d
# add the needed entry at the end of the table;
# sed(1) does not properly interpret the '$a'
# construct if you previously deleted the last
# line, so the command
# $a\
# rb:023456:wait:/usr/robot/bin/setup #ROBOT
# will not work here if the file already contained
# the modification. Instead, you will settle for
# inserting the entry before the last line!
$i\
rb:023456:wait:/usr/robot/bin/setup #ROBOT