pre-commit

#!/bin/bash
#
# An example hook script to verify what is about to be committed.
# Called by "git commit" with no arguments.  The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.
#
# To enable this hook, rename this file to "pre-commit".

if git rev-parse --verify HEAD >/dev/null 2>&1
then
	against=HEAD
else
	# Initial commit: diff against an empty tree object
	against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

# Redirect output to stderr.
exec 1>&2

TF=$(mktemp)
trap "rm -f $TF" 0 1 2 3 15
checkstdin() {
    sort -f | uniq -di > $TF
    cat $TF
    test -s $TF || return 0   # if $TF is empty, we are good
    echo "non-unique (after case folding) names found!" 1>&2
    cat $TF 1>&2
    return 1
}

git ls-files | checkstdin || {
    echo "ERROR - file name collision, check case of names, stopping commit" 1>&2
    exit 1
}