This lives on our git server as /usr/local/bin/git and advises people where they went wrong when creating a new repo.

output

$ git init
 ________________________________________
/ Friends don't let friends run git init \
\ without --shared                       /
 ----------------------------------------
\                             .       .
 \                           / `.   .' " 
  \                  .---.  <    > <    >  .---.
   \                 |    \  \ - ~ ~ - /  /    |
         _____          ..-~             ~-..-~
        |     |   \~~~\.'                    `./~~~/
       ---------   \__/                        \__/
      .'  O    \     /               /       \  " 
     (_____,    `._.'               |         }  \/~~~/
      `----.          /       }     |        /    \__/
            `-.      |       /      |       /      `. ,~~|
                ~-.__|      /_ - ~ ^|      /- _      `..-'   
                     |     /        |     /     ~-.     `-. _  _  _
                     |_____|        |_____|         ~ - . _ _ _ _ _>

usr_local_bin_git

#!/bin/bash
#
# Wrapper to stop people creating repos without the --shared option.
# So that there are fewer ragepunches.

YOUR_ACTUAL_GIT='/usr/bin/git'

if [ "$1" = 'init' ] && ! echo "$@" | egrep -q -- '[[:space:]]--shared([[:space:]]|$)'
then
    cowsay -f stegosaurus \
      "Friends don't let friends run git init without --shared"
    exit 999
else
    exec $YOUR_ACTUAL_GIT "$@"
fi