find_unused_cpan_modules.sh

#!/usr/bin/env bash
#  vim:ts=4:sts=4:sw=4:et
#
#  Author: Hari Sekhon
#  Date: 2019-02-27 11:52:24 +0000 (Wed, 27 Feb 2019)
#
#  https://github.com/harisekhon/bash-tools
#
#  License: see accompanying Hari Sekhon LICENSE file
#
#  If you're using my code you're welcome to connect with me on LinkedIn and optionally send me feedback to help steer this or other code I publish
#
#  https://www.linkedin.com/in/harisekhon
#

# Script to find unused Perl CPAN module requirements in the current directory tree

set -euo pipefail
[ -n "${DEBUG:-}" ] && set -x
srcdir="$(dirname "$0")"

# shellcheck disable=SC1090
. "$srcdir/lib/utils.sh"

# shellcheck disable=SC2034
usage_args="<files>"

for x in "$@"; do
    case "$x" in
    -h|--help)  usage
                ;;
    esac
done

found=0

while read -r module; do
        # grep -R is sloooow by comparison to git grep
    if ! \
        git grep "^[[:space:]]*\(use\|require\|import\)[[:space:]]\+$module" |
        grep -v 'cpan-requirements.*.txt' |
        grep -q .; then
            echo "$module"
            ((found + 1))
    fi
done < <(
    sed 's/#.*//;
         s/@.*//;
         s/^[[:space:]]*//;
         s/[[:space:]]*$//;
         /^[[:space:]]*$/d;' "$@" |
    sort -u
)

if [ $found -gt 0 ]; then
    exit 1
fi