cdup bash function

cdup.func.sh

cdup() {
        p=${1}
        if [[ $p = -* ]]; then
                c="cd "
                while [[ $p -lt 0 ]]; do
                        c=$c"../"
                        let p=p+1
                done
                $c
        else
                a=$(pwd)
                #remove current dir
                b=${a%/*}
                #build cd
                c="cd "${b%$1*}$1
                $c
        fi
}

_cdup_complete() {
        local cur prev path ar opts
        COMPREPLY=()
        cur="${COMP_WORDS[COMP_CWORD]}"
        prev="${COMP_WORDS[COMP_CWORD-1]}"
        path=$(pwd)
        old_ifs=$IFS
        IFS=/
        ar=$path
        opts=""
        for x in $ar; do
                opts=$opts$x" "
        done
        IFS=$old_ifs
        COMPREPLY=( $(compgen -W "${opts}" ${cur}) )
}