Go to the first, previous, next, last section, table of contents.

# 6. Using `gzip` on tapes

When writing compressed data to a tape, it is generally necessary to pad the output with zeroes up to a block boundary. When the data is read and the whole block is passed to `gunzip` for decompression, `gunzip` detects that there is extra trailing garbage after the compressed data and emits a warning by default. You have to use the ``--quiet'` option to suppress the warning. This option can be set in the `GZIP` environment variable, as in:

    for sh:    GZIP="-q"  tar -xfz --block-compress /dev/rst0
    for csh:   (setenv GZIP "-q"; tar -xfz --block-compress /dev/rst0)

In the above example, `gzip` is invoked implicitly by the ``-z'` option of GNU `tar`. Make sure that the same block size (``-b'` option of `tar`) is used for reading and writing compressed data on tapes. (This example assumes you are using the GNU version of `tar`.)

Go to the first, previous, next, last section, table of contents.