preinst is in snort-common 2.9.7.0-5.
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 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50  | #!/bin/sh
set -e
# summary of how this script can be called:
#        * <new-preinst> `install'
#        * <new-preinst> `install' <old-version>
#        * <new-preinst> `upgrade' <old-version>
#        * <old-preinst> `abort-upgrade' <new-version>
GENCONF="/etc/snort/snort.conf" # generic configuration file
DBCONF="/etc/snort/database.conf" # deprecated
case "$1" in
    install)
        # Do nothing
    ;;
    upgrade)
         # versions previous to 2.9.3 created the /etc/snort/database.conf
         # file for configuration
         #if dpkg --compare-versions "$2" le "2.9.3" &&  [ -e "$DBCONF" ] && ! [ -s "$DBCONF" ] 
         #then
         #
         # should show a warning to the user if not empty?
         # (it will be deprecated anyway and will not be included in snort.conf)
         #
         #fi
         # Remove the database configuration file it is exists and is empty
         if  [ -e "$DBCONF" ] && ! [ -s "$DBCONF" ] 
         then
                rm -f $DBCONF
         fi
    ;;
    configure)
        # Do nothing
    ;;
    abort-upgrade)
    ;;
    *) 
        echo "preinst called with unknown argument \`$1'" >&2
        exit 0
    ;;
esac
# dh_installdeb will replace this with shell code automatically
# generated by other debhelper scripts.
exit 0
 |