docs/121713: man page for su contains errornous example.

[Chris St Denis]

>Number:         121713
>Category:       docs
>Synopsis:       man page for su contains errornous example.
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Mar 14 21:20:01 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Chris St Denis
>Release:        7.0-RELEASE
>Organization:
Smarttnet
>Environment:
FreeBSD 7.0-RELEASE FreeBSD 7.0-RELEASE #1: Mon Feb 25 11:51:25 PST 2008 i386

>Description:
the man page for the "su" command contains the examples

     su man -c catman
            Runs the command catman as user man.  You will be asked for man's
            password unless your real UID is 0.
     su man -c 'catman /usr/share/man /usr/local/man'
            Same as above, but the target command consists of more than a sin-
            gle word and hence is quoted for use with the -c option being
            passed to the shell.  (Most shells expect the argument to -c to be
            a single word).

These examples do not work because man has the nologin shell, producing the results

mail# su man -c catman
This account is currently not available.

>How-To-Repeat:

>Fix:
These examples should be changed or removed. Since there doesn't appear to be any BSD equivalent of the linux --shell parameter for su another user & command will have to be chosen. 

>Release-Note:
>Audit-Trail:
>Unformatted: