better rvm use

gistfile1.pl

rvmuse () {
    if [ -d ~/.rvm/gems ]; then
	rvmdir=~/.rvm/gems
    else
	if [ -d /usr/local/rvm/gems ]; then
	    rvmdir=/usr/local/rvm/gems
	else
	    echo "RVM installed?"
	    return
	fi
    fi
    gemsets=$(grep '@' < <(cd $rvmdir; find . -maxdepth 1 -type d )|sort)
    set $gemsets
    x=0
    while [ $# -gt 0 ];do 
	((x=$x+1))
	echo $x"): "$1 >&2
	shift
    done
    read line
    x=0
    set $gemsets
    while [ $# -gt 0 ];do 
	((x=$x+1))
	if [ "$line" = "$x" ]; then
	    eval "rvm use "$(echo $1 | cut -d/ -f2-)
	fi
	shift
    done
}