preinst is in nbd-client 1:2.9.25-2ubuntu1.
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 | #!/bin/sh -e
if [ "$1" = install ] || [ "$1" = upgrade ]; then
if [ -e "/etc/modprobe.d/nbd-client" ]; then
if [ "`md5sum \"/etc/modprobe.d/nbd-client\" | sed -e \"s/ .*//\"`" = \
"`dpkg-query -W -f='${Conffiles}' nbd-client | sed -n -e \"\\\\' /etc/modprobe.d/nbd-client's/.* //p\"`" ]
then
rm -f "/etc/modprobe.d/nbd-client"
fi
fi
fi
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