[ diff_options ] file1
[ file2 ]
.SH DESCRIPTION
-.P
.I Zcmp
and
.I zdiff
.I cmp
or
.IR diff "."
-If only one file is specified, then it is compared to a file with the same name
-without the
-.I ".gz"
-extension. If two files are specified, then they are uncompressed if necessary
-and fed to
+If only
+.I file1
+is specified, it is compared to the uncompressed contents of
+.IR file1 ".gz."
+If two files are specified, their contents (uncompressed if necessary) are fed to
.I cmp
or
.IR diff "."
+The input files are not modified.
The exit status from
.I cmp
or
.I cmp
or
.I diff
-programs refer to temporary filenames instead of those specified.
+programs may refer to file names such as "\-" instead of to the file
+names specified.