The files under this directory with a .Z suffix are compressed with
4.3BSD-Quasijarus UNIX compress(1) utility in the strong compression (-s) mode.
If you are running 4.3BSD-Quasijarus UNIX, you can use uncompress(1) or zcat(1)
to uncompress these files. If you are running an earlier version of UNIX, you
can upgrade your compress(1) utility to the 4.3BSD-Quasijarus version to
understand the -s format. The 4.3BSD-Quasijarus compress(1) utility can be
found in /pub/UNIX/components/compress.tar on this FTP site.

If you would rather download these files in the gzip (.gz) format, you can
request a .gz file (e.g., if you see file.tar.Z in the directory listing,
request file.tar.gz) and the FTP server will convert it for you on the fly.
Since the compress -s and gzip formats are so close, the conversion does not
noticeably slow down the download.