prepare_dir_bak

#!/bin/bash

option_list=("TYPE" "DIR_NAME" "DO_BACKUP" "USE_EXISTING" "VERBOSE")
USAGE="Usage: $(basename ${0}) ${option_list[@]}

Prepare a directory and retain, remove, or back up a possible pre-existing directory of the same name.

Options:
 - TYPE: Short description used in prints, e.g. \"backup\" or \"output\".
 - DIR: Name of the directory.
 - DO_BACKUP (true|false): Retain a pre-existing directory of the same name as '*.bak'.
 - USE_EXISTING (true|false): Retain a pre-existing directory as-is, including its contents.
 - VERBOSE (true|false): Print verbose output."

main()
{
    # Eval inargs
    local nargs_min=5
    if [[ ${#} -lt ${nargs_min} ]]
    then
        echo "${USAGE}"
        return 1
    fi
    local name="${1}"
    local dirname="${2}"
    local do_backup=${3}
    local use_existing=${4}
    local verbose=${5}

    # Set verbosity flag for commands
    [[ "${verbose}" == "true" ]] && vflag="-v" || vflag=""

    # Handle pre-existing directory: skip, remove, or back it up
    if [[ -d "${dirname}" ]]
    then

        # Use the existing directory
        if ${use_existing}
        then
            if ${verbose}
            then
                echo "using existing ${name} directory: ${dirname}"
            fi
            return
        fi

        # Retain a backup-copy of the existing directory
        if [[ "${do_backup}" == "true" ]]
        then
            bak="${dirname}.bak"
            if ${verbose}
            then
                echo "warning: ${name} directory already exists: ${dirname}" >&2
                echo "saving as ${bak}" >&2
            fi
            if [[ -d "${bak}" ]]
            then
                if ${verbose}
                then
                    echo "warning: overwriting existing ${name} directory '${bak}'" >&2
                fi
                \rm -rf ${vflag} "${bak}"
            fi
            \mv -v "${dirname}" -T "${bak}"

        # Remove the existing directory
        else
            if ${verbose}
            then
                echo "warning: overwriting existing ${name} directory '${dirname}'" >&2
            fi
            \rm -rf ${vflag} "${dirname}"
        fi
    fi

    # Create the new directory
    \mkdir -p ${vflag} "${dirname}"
}

main "${@}"