+.PP
+Because
+.B mhpath
+expands and sorts
+.RI [ msgs ].
+the command
+.PP
+.RS 5
+.nf
+mv `mhpath 501 500`
+.fi
+.RE
+.PP
+to will not move 501 to 500.
+Quite the reverse. But
+.PP
+.RS 5
+.nf
+mv `mhpath 501` `mhpath 500`
+.fi
+.RE
+.PP
+will do the trick.
+.PP
+Out-of-range message 0 produces a different error message than large
+out-of-range message numbers. But both cause
+.B mhpath
+to exit with non-zero status.