Add/remove a marked section from a config file

cfgsection

#!/bin/bash

CMD=$(basename $0)
SED=$(which sed)
GREP=$(which grep)
ECHO=$(which echo)
CUT=$(which cut)
CAT=$(which cat)


usage()
{
    ${ECHO} "usage:"
    ${ECHO} "${CMD} add --delimiter=<DELIMITER> file-path < <CONTENT>"
    ${ECHO} "${CMD} remove --delimiter=<DELIMITER> file-path"
}


MODE=
DELIMITER=
FILEPATH=


if [ ${#} -lt 3 -o ${#} -gt 3 ]; then
    usage
    exit 0
fi


while [ ${#} -ge 1 ]; do

    ARG=${1}

    case "${ARG}" in

        add|remove)
            MODE=${ARG}
            ;;
        --delimiter*)
            DELIMITER=$(${ECHO} ${ARG} | ${CUT} -f 2 -d '=')
            ;;
        *)
            FILEPATH=${ARG}
            ;;
    esac

    shift
done

if [ -z "${DELIMITER}" ]; then
    ${ECHO} "no delimiter specified"
    usage
    exit 1
fi

if [ ! -f "${FILEPATH}" ]; then
    ${ECHO} "file '${FILEPATH}' does not exist"
    exit 2
fi


BEGIN="# BEGIN:${DELIMITER}"
END="# END:${DELIMITER}"

${GREP} "${BEGIN}" "${FILEPATH}" >/dev/null 2>&1
RC=${?}
if [ ${RC} -eq 0 -a "${MODE}" = "add" ]; then
    ${ECHO} "section already in file."
    exit 3
fi

if [ "${MODE}" = "add" ]; then
cp "${FILEPATH}" "${FILEPATH}.old"
${CAT} >> "${FILEPATH}" <<-EOF

${BEGIN}
$(${CAT})
${END}

EOF
elif [ "${MODE}" = "remove" ]; then
${SED} -i".old" -e "/^${BEGIN}$/,/^${END}$/d" "${FILEPATH}"
fi

#exit 0