That's odd. I can't reproduce the problem on Fedora 17, with either the bundled gzip (1.4) or with gzip 1.5 (which I built myself). For example:
$ rm test.gz x.gz $ : | gzip >test.gz $ dd if=/dev/zero bs=1 count=77 >> test.gz 77+0 records in 77+0 records out 77 bytes (77 B) copied, 0.000514876 s, 150 kB/s $ dd if=test.gz count=1 bs=22 > x.gz 1+0 records in 1+0 records out 22 bytes (22 B) copied, 0.000159583 s, 138 kB/s $ gunzip -tv x.gz x.gz: gzip: x.gz: decompression OK, trailing zero bytes ignored OK $ dd if=test.gz count=1 bs=21 > x.gz 1+0 records in 1+0 records out 21 bytes (21 B) copied, 0.0446526 s, 0.5 kB/s $ gunzip -tv x.gz x.gz: gzip: x.gz: decompression OK, trailing zero bytes ignored OK $ dd if=test.gz count=1 bs=20 > x.gz 1+0 records in 1+0 records out 20 bytes (20 B) copied, 0.0646803 s, 0.3 kB/s $ gunzip -tv x.gz x.gz: OK This all looks right. (You wrote that the last output was "unexpected", but the compressed file is 20 bytes, right? so the 20-byte copy should work.) For the 21-byte case, can you please send the output of the command strace -o trace.txt gunzip -tv x.gz That is, what gets put into the file trace.txt?
