# cd_cache.sh#### Create a new cachable `cd'##_GOTO_CACHE_SIZE=32declare -a DIRScd(){    local i d    local dst=$1    local RETVAL    if [ $# -eq 0 ]; then        builtin cd        return $?    fi    if [ ! -d $dst ]; then        for ((i=0; $i<${#DIRS[@]}; i=$i+1)); do            if [ "$dst" = "$i" ]; then                builtin cd "${DIRS[$i]}"                return $?            fi        done    fi    builtin cd "$dst"    RETVAL=$?    if [ $RETVAL -ne 0 ]; then        return $RETVAL    fi    # Ignore existing entry    for d in ${DIRS[@]}; do        if [ "$d" = "$PWD" ]; then            return 0        fi    done    # Push entry in "FIFO" mode    if [ ${#DIRS[@]} -lt $_GOTO_CACHE_SIZE ]; then        DIRS[${#DIRS[@]}]=$PWD    else        for ((i=0; $i<$_GOTO_CACHE_SIZE; i=$i+1)); do            DIRS[$i]=${DIRS[$i+1]}        done        DIRS[$_GOTO_CACHE_SIZE-1]=$PWD    fi    # Export env. variable d0, d1, d2, ...    for ((i=0; $i<${#DIRS[@]}; i=$i+1)); do        export d$i=${DIRS[$i]}    done    return $RETVAL}lsd(){    local i=0 d    for d in ${DIRS[@]}; do        echo "$i \$d$i $d"        ((i=$i+1))    done}