_p4()
{
    local cur prev p4cmds 
    COMPREPLY=()
    cur="${COMP_WORDS[COMP_CWORD]}"
    prev="${COMP_WORDS[COMP_CWORD-1]}"
    p4cmds=$(p4 help commands | awk '{print $1}')

    case "${prev}" in
        -u) 
            COMPREPLY=( $(compgen -W "$(p4 users | awk '{print $1}')" ${cur}) )
            return 0
            ;;
        -c)
            COMPREPLY=( $(compgen -W "$(p4 clients | awk '{print $2}')" ${cur}) )
            return 0
            ;;
         *)
            COMPREPLY=( $(compgen -W "${p4cmds}" ${cur}) )
            return 0
            ;; 
    esac 
}
complete -F _p4 p4