How to extract .gz file content by gunzip utility

Like the windows, gz is common compression utility in Linux. This guide is to extract content of the .gz file by gunzip utility. Here is the command to see and extract content of the gz file.

View gz file content

gunzip -c mybackup.gz

Extract file file content in another file. you can use different file extension depend on the content of file.

gunzip -c mybackup.gz > mybackup.sql

Compress the mybackup.sql file as mybackup.gz in the current directory.

gunzip -c mybackup.sql > mybackup.gz

Here is the full details of the gzip command.


Syntax

gzip [ -acdfhlLnNrtvV19 ] [-S suffix] [ name … ]

gunzip [ -acfhlLnNrtvV ] [-S suffix] [ name … ]

-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 Decompress.
-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 ouput: let zcat behave as cat. If -f is not given, and when not running in the back ground, 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

The uncompressed size is given as -1 for files not in gzip format, such as compressed .Z files. To get the uncompressed size for such a file, you can use:

zcat file.Z | wc -c

In combination with the –verbose option, the following fields are also displayed:

method: compression method

crc: the 32-bit CRC of the uncompressed data

date & time: time stamp for the uncompressed file

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 format.

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.
-L–licence 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 Use suffix .suf instead of .gz. Any suffix can be given, but suffixes other than .z and .gz should be avoided to avoid confusion when files are transferred to other systems. A null suffix forces gunzip to try decompression on all given files regardless of suffix, as in:gunzip -S “” * (*.* for MSDOS)Previous versions of gzip used the .z suffix. This was changed to avoid a conflict with pack.
-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).

Written by Bala Krishna

Bala Krishna is web developer and occasional blogger from Bhopal, MP, India. He like to share idea, issue he face while working with the code.

This article has 3 comments

  1. cak

    I think you want to use -d to decompress, you useless prick.

  2. Na Nonu

    I think I read somewhere that insects are attracted to a dark spot they see within the light. Like a reverse tunnel.