postinst is in vim-gtk-py2 2:7.4.1689-3ubuntu1.
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 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 | #!/bin/sh
set -e
pkg=vim-gtk-py2
variant=gtk-py2
mandir=/usr/share/man
# two things to do:
# 1) add /usr/bin/vim.variant as alternative for /usr/bin/vim. Priority are
#    chosen accordingly to the principle: ``more features, higher priority''
# 2) add /usr/bin/gvim as an alternative for gnome-text-editor for variants
#    built with gnome support. Same principle for the priority above, with the
#    additional constraint that priority should not be higher than gedit's
add_gnome_alternative () {
  if [ -f /usr/bin/gvim ]; then
    update-alternatives --install /usr/bin/gnome-text-editor \
      gnome-text-editor /usr/bin/vim.$variant $1 \
      --slave $mandir/man1/gnome-text-editor.1.gz gnome-text-editor.1.gz \
              $mandir/man1/vim.1.gz
  fi
}
add_variant_alternative () {
  if [ "$variant" != "tiny" ]; then
    update-alternatives --install /usr/bin/vim vim /usr/bin/vim.$variant $1
    update-alternatives --install /usr/bin/vimdiff vimdiff /usr/bin/vim.$variant $1
    update-alternatives --install /usr/bin/rvim rvim /usr/bin/vim.$variant $1
  fi
  update-alternatives --install /usr/bin/rview rview /usr/bin/vim.$variant $1
  # Since other packages provide these commands, we'll setup alternatives for
  # their manpages, too.
  for i in vi view ex editor ; do
    update-alternatives \
      --install /usr/bin/$i $i /usr/bin/vim.$variant $1 \
      --slave $mandir/fr/man1/$i.1.gz $i.fr.1.gz $mandir/fr/man1/vim.1.gz \
      --slave $mandir/it/man1/$i.1.gz $i.it.1.gz $mandir/it/man1/vim.1.gz \
      --slave $mandir/pl/man1/$i.1.gz $i.pl.1.gz $mandir/pl/man1/vim.1.gz \
      --slave $mandir/ru/man1/$i.1.gz $i.ru.1.gz $mandir/ru/man1/vim.1.gz \
      --slave $mandir/ja/man1/$i.1.gz $i.ja.1.gz $mandir/ja/man1/vim.1.gz \
      --slave $mandir/man1/$i.1.gz $i.1.gz \
              $mandir/man1/vim.1.gz
  done
  case "$variant" in
    gtk*|gtk3*|gnome*|athena*) # gui enabled variants
      add_gui_variant_alternative $1
      ;;
  esac
}
add_gui_variant_alternative () {
  for i in gvim gview rgview rgvim evim eview gvimdiff ; do
    update-alternatives --install /usr/bin/$i $i /usr/bin/vim.$variant $1
  done
}
case "$pkg" in
  vim-tiny)
    add_variant_alternative 10
    ;;
  vim)
    add_variant_alternative 30
    ;;
  vim-nox)
    add_variant_alternative 40
    ;;
  vim-gtk|vim-gtk3|vim-athena)
    add_variant_alternative 50
    ;;
  vim-gnome) # gnome enabled variant
    add_variant_alternative 60
    add_gnome_alternative 45
    ;;
  vim-nox-py2)
    add_variant_alternative 39
    ;;
  vim-gtk-py2|vim-gtk3-py2|vim-athena-py2)
    add_variant_alternative 49
    ;;
  vim-gnome-py2) # gnome enabled variant
    add_variant_alternative 59
    add_gnome_alternative 44
esac
exit 0
 |