Gzip reduces the size of the named files using Lempel-Ziv coding (LZ77). Whenever possible, each file is replaced by one with the extension .gz, while keeping the same ownership modes, access and modification times. If no files are specified, or if a file name is "-", the standard input is compressed to the standard output. Gzip will only attempt to compress regular files. In particular, it will ignore symbolic links.
This option does nothing on Linux systems.
Write output on standard output; keep original files unchanged. If there are several input files, the output consists of a sequence of independently compressed members. To obtain better compression, concatenate all input files before compressing them.
Decompress.
Force compression or decompression even if the file has multiple links or the corresponding file already exists, or if the compressed data is read from or written to a terminal. If the input data is not in a recognized by gzip, and if the option --stdout is also given, copy the input data without change to the standard ouput: let zcat behave as cat. If -f is not given, and when not running in the background, gzip prompts to verify whether an existing file should be overwritten.
For each compressed file, list the compressed size, uncompressed size, ration and uncompressed name.
The uncompressed size is given as -1 for files not in gzip .
In combination with the --verbose option, the method, crc and timestamp for the uncompress file is also displayed.
The compression methods currently supported are deflate, compress, lzh (SCO compress -H) and pack. The crc is given as ffffffff for a file not in gzip .
With --name, the uncompressed name, date and time are those stored within the compress file if present.
With --verbose, the size totals and compression ratio for all files is also displayed, unless some sizes are unknown. With --quiet, the title and totals lines are not displayed.
Display the gzip license and quit.
When compressing, do not save the original file name and time stamp by default. (The original name is always saved if the name had to be truncated.) When decompressing, do not restore the original file name if present (remove only the gzip suffix from the compressed file name) and do not restore the original time stamp if present (copy it from the compressed file). This option is the default when decompressing.
When compressing, always save the original file name and time stamp; this is the default. When decompressing, restore the original file name and time stamp if present. This option is useful on systems which have a limit on file name length or when the time stamp has been lost after a file transfer.
Suppress all warnings.
Travel the directory structure recursively. If any of the file names specified on the command line are directories, gzip will descend into the directory and compress all the files it finds there (or decompress them in the case of gunzip).
Use suffix .suf instead of .gz.
Test. Check the compressed file integrity.
Verbose. Display the name and percentage reduction for each file compressed or decompressed.
Version. Display the version number and compilation options then quit.
Regulate the speed of compression using the specified digit #, where -1 or --fast indicates the fastest compression method (less compression) and -9 or --best indicates the slowest compression method (best compression). The default compression level is -6 (that is, biased towards high compression at expense of speed).