This script adds a pre-commit hook to your Git repository that checks for any filenames that contain characters illegal in Windows. Whenever you attempt to commit changes, this hook will run and prevent commits that include such filenames.

add-illegal-windows-filename-check-pre-commit.sh

#!/bin/bash

# add-illegal-windows-filename-check-pre-commit.sh: Sets up a pre-commit hook to check for illegal Windows filename characters
# Author: Jonathan Joewono (jogerj)
# Date: 12 Feb 2024
# Version: 0.1.0

# DESCRIPTION:
# This script adds a pre-commit hook to your Git repository that checks for any filenames that contain
# characters illegal in Windows. Whenever you attempt to commit changes, this hook will run and prevent
# commits that include such filenames.

# USAGE:
#  1. Add this file to your git repo folder and run `chmod +x add-illegal-windows-filename-check-pre-commit.sh`
#  2. Run `./add-illegal-windows-filename-check-pre-commit.sh`
#  3. You may delete this setup script from the repo after running it. Subsequent commits will trigger the pre-commit check.

# The script will output an error message if it detects any illegal filename characters, and the commit will be aborted.
# No further action is required once the pre-commit hook is set up.

HOOKS_DIR=".git/hooks"

if [ ! -d "$HOOKS_DIR" ]; then
  mkdir -p "$HOOKS_DIR"
fi

PRE_COMMIT_HOOK="$HOOKS_DIR/pre-commit"

if [ ! -f "$PRE_COMMIT_HOOK" ]; then
  # Add shebang header if new file
  echo -e '#!/bin/sh' >> "$PRE_COMMIT_HOOK"
fi

cat << 'EOF' >> "$PRE_COMMIT_HOOK"

# Command to check for invalid characters in filenames in Windows
ILLEGAL_FILENAMES=$(git diff --cached --name-only | grep -vP '^(?!(?:PRN|AUX|CLOCK\$|NUL|CON|COM\d|LPT\d)(?:\..+)?$)[^\x00-\x1F\xA5\\?*:"";|\/<>]+(?<![\s.])$')
if [ ! -z "$ILLEGAL_FILENAMES" ]]; then
  echo "These filenames contain characters which are not allowed on Windows!\n$ILLEGAL_FILENAMES"
  exit 1
fi
EOF

chmod +x "$PRE_COMMIT_HOOK"

echo "Pre-commit hook added successfully."