cleanup-junk-files.sh

#!/bin/sh

########################################################################
# cleanup-junk-files.sh: Clean Up Junk Files
#
#  Description:
#  This script removes common junk files from a specified directory.
#  It targets files like .DS_Store, ._* AppleDouble files, temporary
#  Unix files ending with '.un~', and __pycache__ directories.
#
#  Author: id774 (More info: http://id774.net)
#  Source Code: https://github.com/id774/scripts
#  License: The GPL version 3, or LGPL version 3 (Dual License).
#  Contact: idnanashi@gmail.com
#
#  Usage:
#      ./cleanup-junk-files.sh <target_directory>
#  Example:
#      ./cleanup-junk-files.sh /path/to/directory
#
#  Notes:
#  - This script will recursively delete the specified junk files in the target directory.
#  - Use with caution and ensure that the target directory is correct.
#  - It is advisable to perform a dry run or backup important files before execution.
#
#  Version History:
#  v2.1 2025-12-20
#       Guard against home directory target by resolving and comparing physical paths.
#  v2.0 2025-12-15
#       Guard against root directory target, fix '*.un~' match, add type filters,
#       and use batched '-exec ... +' for efficiency.
#  v1.9 2025-06-23
#       Unified usage output to display full script header and support common help/version options.
#  v1.8 2025-04-13
#       Unify log level formatting using [INFO], [WARN], and [ERROR] tags.
#  v1.7 2025-03-22
#       Unify usage information by extracting help text from header comments.
#  v1.6 2025-03-16
#       Encapsulated all logic in functions and introduced main function.
#  v1.5 2025-03-13
#       Redirected error messages to stderr for better logging and debugging.
#  v1.4 2024-01-07
#       Updated command existence and execution permission checks
#       using a common function for enhanced reliability and maintainability.
#  v1.3 2023-12-23
#       Refactored for POSIX compliance. Replaced Bash-specific syntax
#       with POSIX standard commands and structures. Enhanced portability
#       and compatibility across different UNIX-like systems.
#  v1.2 2023-12-20
#       Added feature to remove __pycache__ directories.
#  v1.1 2023-12-06
#       Refactored for improved readability, added detailed comments and notes.
#  v1.0 2016-08-05
#       Initial release.
#
########################################################################

# Display full script header information extracted from the top comment block
usage() {
    awk '
        BEGIN { in_header = 0 }
        /^#{10,}$/ { if (!in_header) { in_header = 1; next } else exit }
        in_header && /^# ?/ { print substr($0, 3) }
    ' "$0"
    exit 0
}

# Check if required commands are available and executable
check_commands() {
    for cmd in "$@"; do
        cmd_path=$(command -v "$cmd" 2>/dev/null)
        if [ -z "$cmd_path" ]; then
            echo "[ERROR] Command '$cmd' is not installed. Please install $cmd and try again." >&2
            exit 127
        elif [ ! -x "$cmd_path" ]; then
            echo "[ERROR] Command '$cmd' is not executable. Please check the permissions." >&2
            exit 126
        fi
    done
}

# Resolve a directory path to an absolute physical path
resolve_dir_path() {
    dir="$1"
    (
        cd "$dir" 2>/dev/null || exit 1
        pwd -P 2>/dev/null || pwd
    )
}

# Refuse dangerous target such as root directory
guard_target_dir() {
    target="$1"

    target_real=$(resolve_dir_path "$target")
    if [ -z "$target_real" ]; then
        echo "[ERROR] Failed to resolve target directory: $target" >&2
        exit 1
    fi

    if [ "$target_real" = "/" ]; then
        echo "[ERROR] Refuse to operate on '/'" >&2
        exit 1
    fi

    if [ -n "$HOME" ]; then
        home_real=$(resolve_dir_path "$HOME")
        if [ -n "$home_real" ] && [ "$target_real" = "$home_real" ]; then
            echo "[ERROR] Refuse to operate on HOME directory: $home_real" >&2
            exit 1
        fi
    fi
}

# Perform cleanup of junk files
cleanup_junk_files() {
    echo "[INFO] Cleaning up junk files in $1..."

    echo "[INFO] Removing ._* AppleDouble files..."
    find "$1" -type f -name '._*' -exec rm -f {} +

    echo "[INFO] Removing .DS_Store files..."
    find "$1" -type f -name '.DS_Store' -exec rm -f {} +

    echo "[INFO] Removing temporary Unix files ending with '.un~'..."
    find "$1" -type f -name '*.un~' -exec rm -f {} +

    echo "[INFO] Removing __pycache__ directories..."
    find "$1" -type d -name '__pycache__' -exec rm -rf {} +

    echo "[INFO] Cleanup completed."
}

# Main entry point of the script
main() {
    case "$1" in
        -h|--help|-v|--version) usage ;;
    esac

    # Check if rm and find commands exist
    check_commands rm find

    if [ "$#" -eq 0 ]; then
        usage
    fi

    if [ -d "$1" ]; then
        guard_target_dir "$1"
        cleanup_junk_files "$1"
    else
        echo "[ERROR] Directory '$1' is not found." >&2
        exit 1
    fi

    return 0
}

# Execute main function
main "$@"