S9 EXT  (sys:getpwnam string)   ==>  alist | #f
        (sys:getpwuid integer)  ==>  alist | #f

Return the password record for the user name STRING or the user
ID INTEGER. The returned association list has the following members:

        ((name  . string)   ; user name
         (uid   . integer)  ; user ID
         (gid   . integer)  ; group ID
         (gecos . string)   ; real name
         (home  . string)   ; home directory
         (shell . string))  ; default shell

When an invalid user name or UID is passed to these procedures, #F
is returned.

(sys:getpwnam "nmh")  ==>  ((name . "nmh")
                            (uid . 1001)
                            (gid . 1001)
                            (gecos . "Nils M Holm")
                            (home . "/u/home/nmh")
                            (shell . "/bin/ksh"))
