Changes in release 4.1:
[4.0q]
+* chown now works properly when the specified login name contains a period
+ This is at the expense of always looking up the entire USER.GROUP string
+ as a login name first, and only then (upon failure) interpreting the `.'
+ as a separator and looking up `USER'. To avoid the extra getpwnam call,
+ always use the POSIX-mandated `:' character as the separator.
* `du some-other-dir' no longer fails if it can't open the current directory
* `mv DIR EXISTING-FILE' no longer removes EXISTING-FILE. Now it gets an error
as POSIX says it must.