Log Message:
Changes 1.6:
The "--keep" (-k) option was added to not delete input files, in line \ 
with other tools such as xz, lzip, and bzip2. A decompression issue with certain \ 
invalid data in the 'pack' format was fixed. An incorrect overwrite when \ 
compiled with optimization was fixed. zgrep's handling of multi-digit context \ 
options was fixed. zmore now acts more like 'more'.