bash thing i found

mkarchroot snip

##
#  usage : in_array( $needle, $haystack )
# return : 0 - found
#          1 - not found
##
in_array() {
        local needle=$1; shift
        local item
        for item in "$@"; do
                [[ $item = $needle ]] && return 0 # Found
        done
        return 1 # Not Found
}