bash script to maintan configuration files in macOS (inspired by mackup)

cfgsync.sh

cfgsync() {
    # Usage: cfgsync {uplink|linkstore|backup|restore|reset} {directory_or_file} [-q|--quiet]
    #        cfgsync backup Clipboard                         # initialize backup, assuming config/ subfolder in backup
    #        cfgsync restore Clipboard/config/clipboard.cfg   # restore to a new machine
    #     
    #        uplink: (backup first + link second) Backs up the original file/folder, according to .cfg, by copying it to a backup location and then creates a symbolic link to the backup in the original place.
    #        linkstore: (link to an existing backup to restore) Restores the original file by removing it (if it exists) and creating a symbolic link to the backup in the original place.
    #        backup: (backup, no link) Backs up the original file/folder, according to .cfg, by copying it to a backup location. No symbolic link is created.
    #        restore: (restore, no link) Similar to linkstore, but instead of creating a symbolic link, it copies the backup back to the original location.
    #        reset: Deletes the original file or symbolic link, with the hope that the application will recreate a default configuration file if necessary.
    #        -q or --quiet to skip confirmation
    # 
    #        cfg format (non-existing file will be skipped):
    #        https://github.com/lra/mackup/tree/master/mackup/applications  (this function hard-codingly converts [xdg_configuration_files] to .config)
    #            [application]
    #            name = Bartender
    #            
    #            [configuration_files]
    #            # assuming $HOME/ prefix
    #            Library/Preferences/com.surteesstudios.Bartender.plist
    #            Library/Preferences/com.surteesstudios.Bartender-setapp.plist
    #            Library/Application Support/Bartender/Bartender.BartenderPreferences
    #            # if path starts with /, then no prefix will be added, use it as is
    #            /Library/Application Support
    #
    #            [xdg_configuration_files]
    #            # assuming $HOME/.config/ prefix
    #            karabiner


    local quiet=$3
    prompt_for_confirmation() {
        local message=$1
        if [[ "$quiet" == "-q" || "$quiet" == "--quiet" ]]; then
            echo "$message ([y]/n):"  # Optionally display the message
            return 0         # Automatically confirm
        fi
        read -p "$message ([y]/n): " response
        response=${response:-y}
        if [[ $response == [Nn]* ]]; then
            echo "User cancelled."
            return 1
        fi
        return 0
    }

    local mode=$1
    local input_path=$2
    local cfg_file=""       # cfg_file in input_path
    local cfg_dir=""        # cfg_dir containing cfg_file
    local plist_files=()    # plist_files extracted from cfg_file
    local line              # loop cfg_file
    local plist_original    # loop plist_files
    local plist_backup      # backup plist_files saved in cfg_dir

    # Determine whether the input is a directory or a specific file
    if [ -d "$input_path" ]; then
        # Remove trailing slash if it exists for input path
        input_path="${input_path%/}"
        cfg_dir="$(realpath ${input_path}/config)"
        # Find the first .cfg file in the directory
        cfg_file="$(find "$cfg_dir" -maxdepth 1 -type f -name '*.cfg' | head -n 1)"
        if [ -z "$cfg_file" ]; then
            echo "No .cfg file found in directory $cfg_dir."
            return 1
        fi
    elif [ -f "$input_path" ]; then
        cfg_file="$(realpath $input_path)"
        cfg_dir="$(realpath $(dirname "$cfg_file"))"
    else
        # echo "Invalid input. Please provide a directory or a .cfg file."
        echo "Usage: cfgsync {uplink|linkstore|backup|restore|reset} {directory_or_file}"
        return 1
    fi

    mode_title_case=$(echo "$mode" | awk '{print toupper(substr($0,1,1)) tolower(substr($0,2))}')
    prompt_for_confirmation "Found $cfg_file. $mode_title_case?"

    # Parse the configuration file to extract file paths
    parseCfg() {
        local in_config_section=false
        local in_xdg_section=false

        while IFS= read -r line || [[ -n "$line" ]]; do
            # Check if the current line is a section header
            if [[ $line =~ ^\[.*\]$ ]]; then
                if [[ $line == "[configuration_files]" ]]; then
                    in_config_section=true
                else
                    in_config_section=false
                fi
                if [[ $line == "[xdg_configuration_files]" ]]; then
                    in_xdg_section=true
                else
                    in_xdg_section=false
                fi
                continue
            fi

            # If we are in the configuration_files section, add non-empty and non-comment lines to the array
            if [[ $in_config_section == true && -n $line && ! $line =~ ^[[:space:]]*# ]]; then
                # /Library/Application Support/
                if [[ $line == /* ]]; then
                    plist_files=("${plist_files[@]}" "${line}")
                else
                    plist_files=("${plist_files[@]}" "$HOME/${line}")
                fi
            fi
            if [[ $in_xdg_section == true && -n $line && ! $line =~ ^[[:space:]]*# ]]; then
                plist_files=("${plist_files[@]}" "$HOME/.config/${line}")
            fi
        done < "$cfg_file"
    }

    parseCfg

    # Apply operations on the extracted file paths
    for plist_original in "${plist_files[@]}"; do
        plist_backup="$cfg_dir/$(basename "$plist_original")"
        
        case $mode in
            uplink)
                # skip if it has already been a soft link
                if [ -L "$plist_original" ]; then
                    local linked_file=$(readlink "$plist_original")
                    if [ "$linked_file" = "$plist_backup" ]; then
                        echo "$plist_original is already a symbolic link to $plist_backup. No need to relink."
                    else
                        # red
                        echo -e "\033[31mCan not uplink! $plist_original is a symbolic link, but not pointing to $plist_backup.\033[0m"
                    fi
                    continue
                fi
                # .cfg may contain unnecessary files
                if [ ! -e "$plist_original" ]; then
                    # grey
                    echo -e "\033[90mIgnored: $plist_original does not exist.\033[0m"
                    continue
                fi
                # remove previous backup, esp. needed if backup is a folder, in order for cp to work properly
                rm -rf "$plist_backup"
                # now we do cp, rm, ln
                cp -r "$plist_original" "$plist_backup"
                rm -r "$plist_original"
                if [ -d "$plist_backup" ]; then
                    ln -sf "$plist_backup" "$(dirname "$plist_original")"
                else
                    ln -sf "$plist_backup" "$plist_original"
                fi
                echo "Symbolic link created for backup of $plist_original."
                ;;
            backup)
                # skip if it is a soft link
                if [ -L "$plist_original" ]; then
                    # red
                    echo -e "\033[31mCan not backup! $plist_original is just a symbolic link.\033[0m"
                    continue
                fi
                # .cfg may contain unnecessary files
                if [ ! -e "$plist_original" ]; then
                    # grey
                    echo -e "\033[90mIgnored: $plist_original does not exist.\033[0m"
                    continue
                fi
                # remove previous backup, esp. needed if backup is a folder, in order for cp to work properly
                rm -rf "$plist_backup"
                # now we do cp
                cp -r "$plist_original" "$plist_backup"
                echo "Backup created for $plist_original."
                ;;
            linkstore)
                # Again, .cfg may contain unnecessary files (if no backup, no restore)
                if [ ! -e "$plist_backup" ]; then
                    echo -e "\033[90mIgnored: $plist_backup does not exist.\033[0m"
                    continue
                fi
                # remove original file (could be a soft link)
                rm -rf "$plist_original"
                # create necessary parent folder if not there
                mkdir -p "$(dirname "$plist_original")"
                # at this point, plist_original should not exist, ln below would work properly esp. when it is a folder
                if [ -d "$plist_backup" ]; then
                    ln -sf "$plist_backup" "$(dirname "$plist_original")"
                else
                    ln -sf "$plist_backup" "$plist_original"
                fi
                echo "Configuration linkstored from backup for $plist_original."
                ;;
            restore)
                # restore is similar to linkstore, except for the last part
                # Again, .cfg may contain unnecessary files
                if [ ! -e "$plist_backup" ]; then
                    echo -e "\033[90mIgnored: $plist_backup does not exist.\033[0m"
                    continue
                fi
                # remove original file (could be a soft link)
                rm -rf "$plist_original"
                # create necessary parent folder if not there
                mkdir -p "$(dirname "$plist_original")"
                # the above are the same as restore
                cp -r "$plist_backup" "$plist_original"
                echo "Backup restored for $plist_original."
                ;;
            reset)
                rm -rf "$plist_original"
                echo "Configuration reset for $plist_original."
                # hopefully a default config file will be auto recreated by the app
                # in case not, I have backups, hopefully already, in the .cfg folder
                ;;
            *)
                echo "Usage: cfgsync {uplink|linkstore|backup|restore|reset} {directory_or_file}"
                return 1
                ;;
        esac
    done
}