zdiff are used to invoke the
cmp or the
diff program on compressed files. All options specified are passed directly to
diff. If only 1 file is specified, then the files compared are
file1 and an uncompressed
file1.gz. If two files are specified, then they are uncompressed if necessary and fed to
diff. The exit status from
diff is preserved.
Messages from the
diff programs refer to temporary filenames instead of those specified.