postinst is in newpid 7.
This file is a maintainer script. It is executed when installing (*inst) or removing (*rm) the package.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | #!/bin/sh
set -e
case $1 in
configure)
setcap "CAP_SYS_ADMIN,CAP_NET_ADMIN=pe" /usr/bin/newpid
;;
esac
|