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'
tar) is used for reading and writing compressed data on
tapes. (This example assumes you are using the GNU version of