postinst is in tex4ht-common 20090611-1.1build1.
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 | #!/bin/sh
set -e
LASTVERSION="20060913-1"
# Snippet taken from http://wiki.debian.org/DpkgConffileHandling
# <snippet>
# Move a conffile without triggering a dpkg question
mv_conffile() {
    OLDCONFFILE="$1"
    NEWCONFFILE="$2"
    if [ -e "$OLDCONFFILE" ]; then
        echo "Preserving user changes to $NEWCONFFILE ..."
        mv -f "$NEWCONFFILE" "$NEWCONFFILE".dpkg-new
        mv -f "$OLDCONFFILE" "$NEWCONFFILE"
    fi
}
case "$1" in
configure)
    if dpkg --compare-versions "$2" le "$LASTVERSION"; then
        mv_conffile "/etc/texmf/texmf.d/90tex4ht.cnf" "/etc/texmf/texmf.d/80tex4ht.cnf"
    fi
esac
# </snippet>
# Update the kpathsea lists
texhash /usr/share/texmf # since we only install files there
update-texmf
 |