Recursively delete Apple Double Files (ADFs) and '.DS_Store' files from a specified directory.

RemoveAppleDoubleFiles.sh

#!/usr/bin/env bash

#--------------------------------------------------------------------------------------------------------
# Name: RemoveAppleDoubleFiles.sh
# Purpose: Recursively remove Apple Double Files (ADFs) and '.DS_Store' files from a specified directory.
# Compatability: GNU/Linux & macOS
# Usage: ./RemoveAppleDoubleFiles.sh [/path/to/dir]
# Notes:
# - ADFs have file names beginning with '._'.
# - ADFs begin with the 'magic' sequence '0x00051607'.
# - '.DS_Store' files commence with '0000 0001' followed by the 'magic' sequence '0x42756431' ("Bud1").
# Sources:
# - https://nulib.com/library/AppleSingle_AppleDouble.pdf
# - https://opensource.apple.com/source/copyfile/copyfile-42/copyfile.c
# - https://0day.work/parsing-the-ds_store-file-format/
#--------------------------------------------------------------------------------------------------------

##################################
# GLOBAL VARIABLES AND CONSTANTS #
##################################

ANSI_RED="\033[1;31m"
ANSI_YELLOW="\033[1;33m"
ANSI_GREEN="\033[1;32m"
ANSI_CLEAR="\033[0m"
readonly ANSI_RED
readonly ANSI_YELLOW
readonly ANSI_GREEN
readonly ANSI_CLEAR

appleDoubleFilePaths=()
DSStoreFilePaths=()
searchDirectory=""

#############
# FUNCTIONS #
#############

function check_dependencies() {
    if ! command -v xxd &>/dev/null; then
        echo -e "${ANSI_RED}[ERROR]${ANSI_CLEAR} Command 'xxd' missing!"
        echo "Please install 'xxd':"
        echo "Debian/Ubuntu"
        echo "    sudo apt install xxd"
        echo "Fedora/RHEL"
        echo "    sudo dnf install vim-common"
        echo "Exiting with status 2."
        exit 2
    fi
}

function confirm_action() {
    local answer=""

    while true; do
        read -p "${1} (y/n): " answer
        answer=$(echo "$answer" | tr '[:upper:]' '[:lower:]') # Convert answer to lowercase.

        # Check if the answer is 'y' or 'n'.
        if [[ "$answer" == "y" ]]; then
            # Double check with the user.
            read -p "I am going to ask you again. Are you absolutely sure? (y/n): " answer
            answer=$(echo "$answer" | tr '[:upper:]' '[:lower:]') # Convert answer to lowercase.
            # Check if the answer is 'y' or 'n'.
            if [[ "$answer" == "y" ]]; then
                break
            elif [[ "$answer" == "n" ]]; then
                return 1
            else
                echo -e "${ANSI_RED}[ERROR]${ANSI_CLEAR} Invalid response. Please answer with either 'y' or 'n'."
            fi
        elif [[ "$answer" == "n" ]]; then
            return 1
        else
            echo -e "${ANSI_RED}[ERROR]${ANSI_CLEAR} Invalid response. Please answer with either 'y' or 'n'."
        fi
    done

    return 0
}

# Check if 'xxd' is available.
check_dependencies

########################
# SET SEARCH DIRECTORY #
########################
if [ -n "$1" ]; then
    # Check if the argument is a valid directory.
    if [ -d "$1" ]; then
        # Set searchDirectory to the provided argument.
        searchDirectory="$1"
    else
        echo -e "${ANSI_RED}[ERROR]${ANSI_CLEAR} '${1}' is not a valid directory!"
        echo "Exiting with status 1."
        exit 1
    fi
else
    # Set searchDirectory to the current working directory.
    searchDirectory=$(pwd)
fi

######################
# APPLE DOUBLE FILES #
######################

# Use a while loop without a pipe to avoid running in a subshell.
while IFS= read -r file; do
    # Header structure:
    # 1. Magic Number       (4 Bytes)       <-- Offset 0x00 (00)     [EXAMPLE: '0005 1607']
    # 2. Version Number     (4 Bytes)       <-- Offset 0x04 (04)     [EXAMPLE: '0002 0000']
    # 3. Filler             (16 Bytes)      <-- Offset 0x08 (08)     [EXAMPLE: '4D61 6320 4F53 2058 2020 2020 2020 2020']
    # 4. Number of Entries  (2 Bytes)       <-- Offset 0x18 (24)     [EXAMPLE: '0002'] (Uint16)
    # Check if the first 4 bytes of the file match the magic hex sequence '0x00051607'.
    if [ "$(xxd -p -l 4 < "$file")" == "00051607" ]; then
        # Append the absolute file path to the array.
        appleDoubleFilePaths+=("$(realpath "$file")")
    fi
done < <(find "$searchDirectory" -name '._*' -type f -print)

if [ ${#appleDoubleFilePaths[@]} -ne 0 ]; then
    # List detected ADFs.
    echo -e "${ANSI_GREEN}DETECTED ADFs!${ANSI_CLEAR}"
    printf "%s\n" "${appleDoubleFilePaths[@]}"
    echo ""

    # Request user permission to delete ADFs.
    confirm_action "Proceed with deletion of the above files?" || {
        echo -e "${ANSI_YELLOW}[WARNING]${ANSI_CLEAR} Operation cancelled by user."
        exit 0
    }

    # Delete ADFs.
    errors=0
    echo ""
    for appleDoubleFile in "${appleDoubleFilePaths[@]}"; do
        echo -e -n "${ANSI_RED}-->${ANSI_CLEAR} Deleting '${appleDoubleFile}'... "
        # Attempt to delete the file.
        if rm -f "$appleDoubleFile"; then
            echo -e "${ANSI_GREEN}OK!${ANSI_CLEAR}"
        else
            echo -e "${ANSI_RED}FAILED!${ANSI_CLEAR}"
            ((errors++))
        fi
    done

    if [ "$errors" -gt 0 ]; then
        echo ""
        echo -e "${ANSI_YELLOW}[WARNING]${ANSI_CLEAR} ${errors} file(s) were unable to be deleted!"
    fi

    echo ""
fi

#####################
# '.DS_Store' FILES #
#####################

# Use a while loop without a pipe to avoid running in a subshell.
while IFS= read -r file; do
    # Header structure:
    # 1. Alignment          (4 Bytes)       <-- Offset 0x00 (00)     [ALWAYS: '0000 0001']
    # 2. Magic Number       (4 Bytes)       <-- Offset 0x04 (04)     [ALWAYS: '4275 6431']
    # Check if 4 bytes at offset 0x4 match the magic hex sequence '0x42756431'.
    if [ "$(xxd -p -s 0x4 -l 4 < "$file")" == "42756431" ]; then
        # Append the absolute file path to the array.
        DSStoreFilePaths+=("$(realpath "$file")")
    fi
done < <(find "$searchDirectory" -name '.DS_Store' -type f -print)

if [ ${#DSStoreFilePaths[@]} -ne 0 ]; then
    # List detected '.DS_Store' files.
    echo -e "${ANSI_GREEN}DETECTED '.DS_Store' FILES!${ANSI_CLEAR}"
    printf "%s\n" "${DSStoreFilePaths[@]}"
    echo ""

    # Request user permission to delete '.DS_Store' files.
    confirm_action "Proceed with deletion of the above files?" || {
        echo -e "${ANSI_YELLOW}[WARNING]${ANSI_CLEAR} Operation cancelled by user."
        exit 0
    }

    # Delete '.DS_Store' files.
    errors=0
    echo ""
    for DSStoreFile in "${DSStoreFilePaths[@]}"; do
        echo -e -n "${ANSI_RED}-->${ANSI_CLEAR} Deleting '${DSStoreFile}'... "
        # Attempt to delete the file.
        if rm -f "$DSStoreFile"; then
            echo -e "${ANSI_GREEN}OK!${ANSI_CLEAR}"
        else
            echo -e "${ANSI_RED}FAILED!${ANSI_CLEAR}"
            ((errors++))
        fi
    done

    if [ "$errors" -gt 0 ]; then
        echo ""
        echo -e "${ANSI_YELLOW}[WARNING]${ANSI_CLEAR} ${errors} file(s) were unable to be deleted!"
    fi

    echo ""
fi

# Exit.
echo -e "${ANSI_GREEN}DONE!${ANSI_CLEAR}"
exit 0