gunzip : compress or expand files
[SYNOPSIS] gunzip OPTION FILE
OPTION
-c write on standard output, keep original files unchanged
-f force overwrite of output file and compress links
-k keep (don't delete) input files
-l list compressed file contents
-n do not save or restore the original name and timestamp
-N save or restore the original name and timestamp
-q suppress all warnings
-r operate recursively on directories
-S, --suffix=SUF use suffix SUF on compressed files
-t test compressed file integrity
-v verbose mode