Linux and UNIX gzip, gunzip, and zcat command help and examples. About gzip, gunzip, and zcatzcat, gunzip, and gzip syntaxzcat, gunzip, and gzip examples. Related commands. Linux and Unix main page. About gzip, gunzip, and zcatgzip, gunzip, and zcat are used to compress or expand files. Descriptiongzip reduces the size of the named files using Lempel- Ziv coding (LZ7. Whenever possible, each file is replaced by one with the extension. The default extension is - gz for VMS, z for MSDOS, OS/2. FAT, Windows NT FAT and Atari.) If no files are specified, or if a file name is "- ", the standard input is compressed to the standard output. In particular, it will ignore symbolic links. If the compressed file name is too long for its file system, gzip truncates it. A part is delimited by dots.) If the name consists of small parts only, the longest parts are truncated. For example, if file names are limited to 1. Names are not truncated on systems which do not have a limit on file name length. By default, gzip keeps the original file name and timestamp in the compressed file. These are used when decompressing the file with the - N option. This is useful when the compressed file name was truncated or when the time stamp was not preserved after a file transfer. Compressed files can be restored to their original form using gzip - d or gunzip or zcat. If the original name saved in the compressed file is not suitable for its file system, a new name is constructed from the original one to make it legal. Z respectively. When compressing, gzip uses the . H or pack. The detection of the input format is automatic. When using the first two formats, gunzip checks a 3. CRC. For pack, gunzip checks the uncompressed length. The standard compress format was not designed to allow consistency checks. Compress multiple files individually with Gzip. Is there a simple Unix way to do it? linux unix compression gzip. Gzip multiple files individually and keep the original files. However gunzip is sometimes able to detect a bad . Z file. If you get an error when uncompressing a . Z file, do not assume that the . Z file is correct simply because the standard uncompress does not complain. This generally means that the standard uncompress does not check its input, and happily generates garbage output. The SCOcompress - H format (lzh compression method) does not include a CRC but also allows some consistency checks. Files created by zip can be uncompressed by gzip only if they have a single member compressed with the 'deflation' method. This feature is only intended to help conversion of tar. To extract a zip file with a single member, use a command like: gunzip < foo. S . zip foo. zip To extract zip files with several members, use unzip instead of gunzip. On some systems, zcat may be installed as gzcat to preserve the original link to compress.) zcat uncompresses either a list of files on the command line or its standard input and writes the uncompressed data on standard output. Lempel- Ziv algorithm used in zip and PKZIP. The amount of compression obtained depends on the size of the input and the distribution of common substrings. Typically, text such as source code or English is reduced by 6. Compression is generally much better than that achieved by LZW (as used in compress), Huffman coding (as used in pack), or adaptive Huffman coding (compact). Compression is always performed, even if the compressed file is slightly larger than the original. Gunzip, gzcat, gzip. compress or expand files. Command. When multiple input files are specified. If you are running gunzip with root priveleges on a UNIX system.The worst case expansion is a few bytes for the gzip file header, plus 5 bytes every 3. K block, or an expansion ratio of 0. Note that the actual number of used disk blocks almost never increases. Ln. Nrtv. V1. 9 ] [- S suffix] [ name .. Ln. Nrtv. V ] [- S suffix] [ name .. LV ] [ name .. ]Options- a, - -ascii. ASCII text mode: convert end- of- lines using local conventions. This option is supported only on some non- Unix systems. You are here: Help > Linux and Unix. Linux and Unix gzip, gunzip, and zcat commands. About gzip, gunzip, and zcat zcat, gunzip, and gzip syntax zcat, gunzip, and gzip examples Related commands Linux and Unix main page. About. Zip Multiple files to One.zip file in AIX system Shell Programming and Scripting. Basic UNIX commands. by typing the command and hitting return. Gzip produces files with the ending '.gz' appended to the original filename. Example uses of the command 'gzip' 2. Linux Command. A Brief Introduction to the Linux Shell Command 'gunzip' What Are TGZ & GZ Files and How Do You Open Them? For MSDOS, CRLF 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 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 sizesize of the compressed fileuncompressed sizesize of the uncompressed fileratiocompression ratio (0. 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: methodcompression methodcrcthe 3. CRC of the uncompressed datadate & timetime 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, - -license. Display the gzip license and exit.- n, - -no- name. When compressing, do not save the original file name and timestamp 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 structurerecursively. 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 . When compressing, use suffix . Any non- empty suffix can be given, but suffixes other than . When decompressing, add . 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). Advanced Usage Multiple compressed files can be concatenated. In this case, gunzip will extract all members at once. For example: gzip - c file. Then: gunzip - c foois equivalent to: cat file. In case of damage to one member of a . However, you can get better compression by compressing all members at once: cat file. If you want to recompress concatenated files to get better compression, do: gzip - cd old. If a compressed file consists of several members, the uncompressed size and CRC reported by the - -list option applies to the last member only. If you need the uncompressed size for all members, you can use: gzip - cd file. If you want to create a single archive file with multiple members so that members can later be extracted independently, use an archiver such as tar or zip. GNUtar supports the - z option to invoke gzip transparently. Environment The environment variable. GZIP can hold a set of default options for gzip. These options are interpreted first and can be overwritten by explicit command line parameters. For example: for sh: GZIP="- 8v - -name"; export GZIP for csh: setenv GZIP "- 8v - -name" for MSDOS: set GZIP=- 8v - -name On Vax/VMS, the name of the environment variable is GZIP_OPT, to avoid a conflict with the symbol set for invocation of the program. Prints the contents of all files within the gzipped tar archive myfiles. Compresses the tar archive backup. Uncompresses the gzipped file backup. Recursively compresses all files in the folder backupfolder, and all files in any subdirectories of that folder, and gives them the extension . Recursively uncompresses all gzipped files in the folder backupfolder, and removes the extension . Compresses the file myfile. The result is that the original file and the gzipped file will both exist after the command is run. Prints the uncompressed contents of the compressed file myfile. The output is identical to printing the contents of the uncompressed file with the command cat myfile. Uncompresses the gzipped file myfile. If myfile. txt already exists, the shell will prompt you to overwrite it (or not). Tip: See the above advanced usage for additinoal exampels. Output the contents of a file. Compress a file or files. Create, modify, list the contents of, and extract files from tar archives. Extract files from compressed archives. List, test and extract compressed files in a zip archive. A compression and archiving utility.
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