|GZIP(1)||General Commands Manual||GZIP(1)|
- -a --ascii
- Ascii text mode: convert end-of-lines using local conventions. This option is supported only on some non-Unix systems. For MSDOS, CR LF is converted to LF when compressing, and LF is converted to CR LF when decompressing.
- -c --stdout --to-stdout
- 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.
- -d --decompress --uncompress
- -f --force
- 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 format recognized by gzip, and if the option --stdout is also given, copy the input data without change to the standard output: 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.
- -h --help
- Display a help screen and quit.
- -l --list
For each compressed file, list the following fields:
compressed size: size of the compressed file
uncompressed size: size of the uncompressed file
ratio: compression ratio (0.0% if unknown)
uncompressed_name: name of the uncompressed file
zcat file.Z | wc -c
method: compression method
crc: the 32-bit CRC of the uncompressed data
date & time: time stamp for the uncompressed file
- -L --license
- Display the gzip license and quit.
- -n --no-name
- 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.
- -N --name
- 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.
- -q --quiet
- Suppress all warnings.
- -r --recursive
- 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 ).
- -S .suf --suffix .suf
When compressing, use suffix .suf instead of .gz. Any non-empty suffix can be given, but suffixes other than .z and .gz should be avoided to avoid confusion when files are transferred to other systems.
- -t --test
- Test. Check the compressed file integrity.
- -v --verbose
- Verbose. Display the name and percentage reduction for each file compressed or decompressed.
- -V --version
- Version. Display the version number and compilation options then quit.
- -# --fast --best
- 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).
gzip -c file1 > foo.gz
gzip -c file2 >> foo.gz
gunzip -c foo
cat file1 file2
cat file1 file2 | gzip > foo.gz
gzip -c file1 file2 > foo.gz
gzip -cd old.gz | gzip > new.gz
gzip -cd file.gz | wc -c
for sh: GZIP="-8v --name"; export GZIP
for csh: setenv GZIP "-8v --name"
for MSDOS: set GZIP=-8v --name
- Usage: gzip [-cdfhlLnNrtvV19] [-S suffix] [file ...]
- Invalid options were specified on the command line.
- file: not in gzip format
- The file specified to gunzip has not been compressed.
- file: Corrupt input. Use zcat to recover some data.
The compressed file has been damaged. The data up to the point of failure can be recovered using
zcat file > recover
- file: compressed with xx bits, can only handle yy bits
- File was compressed (using LZW) by a program that could deal with more bits than the decompress code on this machine. Recompress the file with gzip, which compresses better and uses less memory.
- file: already has .gz suffix -- no change
- The file is assumed to be already compressed. Rename the file and try again.
- file already exists; do you wish to overwrite (y or n)?
- Respond "y" if you want the output file to be replaced; "n" if not.
- gunzip: corrupt input
- A SIGSEGV violation was detected which usually means that the input file has been corrupted.
- xx.x% Percentage of the input saved by compression.
- (Relevant only for -v and -l.)
- -- not a regular file or directory: ignored
- When the input file is not a regular file or directory, (e.g. a symbolic link, socket, FIFO, device file), it is left unaltered.
- -- has xx other links: unchanged
- The input file has links; it is left unchanged. See ln(1) for more information. Use the -f flag to force compression of multiply-linked files.
for sh: GZIP="-q" tar -xfz --block-compress /dev/rst0
for csh: (setenv GZIP -q; tar -xfz --block-compr /dev/rst0
zcat file.gz | wc -c