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Data compression is a technology to reduce the amount of data without losing data information.

Compress

Compress is an ancient compression tool with a .Z suffix for compressed files.

-d: decompress-c: output the result to standard output without deleting the original file-v: display details

Use the example

[root@centos7 / testdir] # compress passwd # Compression [root@centos7 / testdir] # lspasswd.Z [root@centos7 / testdir] # compress-d passwd # decompress gzip

The gzip compressed file has the suffix .gz, and if you compress the tar backup file, the extension is .tar.gz

Gzip, gunzip, zcat-compress or expand files

-d: decompress, equivalent to unzip-c: output the result of compression or decompression to the standard output-#: 1-9, specify the compression ratio zcat: view the contents of the text file without showing the decompression

Gunzip is used to decompress

Zcat is used to view

Use the example

[root@centos7 / testdir] # gzip passwd [root@centos7 / testdir] # lspasswd.gz passwd.Z [root@centos7 / testdir] # [root@centos7 / testdir] # zcat passwd.gz > passwd [root@centos7 / testdir] # lspasswd.gz passwd passwd.Z [root@centos7 / testdir] # bzip2

Bzip2 compressed files have a .bz2 extension

-k: keep, keep the original file-d: decompress-#: 1-9, compression ratio. Default is 6bzcat: view file contents without showing decompression.

Bunzip is used to decompress

Bzcat is used to view unzipped

Use the example

[root@centos7 / testdir] # bzip2 passwd [root@centos7 / testdir] # lspasswd.gz passwd.bz2 passwd.Z [root@centos7 / testdir] # bzcat passwd.bz2 > passwd [root@centos7 / testdir] # lspasswd.gz passwd passwd.bz2 passwd.Z [root@centos7 / testdir] # xz

The xz compressed file has a .xz extension

-k: keep, keep the original file-d: decompress-#: 1-9, compression ratio. Default is 6xzcat: view file contents without showing decompression.

Unxz is used to decompress

Xzcat is used to view

Use the example

[root@centos7 / testdir] # xz passwd [root@centos7 / testdir] # lspasswd.bz2 passwd.gz passwd.xz passwd.Z [root@centos7 / testdir] # [root@centos7 / testdir] # xzcat passwd.xz > passwd [root@centos7 / testdir] # lspasswd passwd.bz2 passwd.gz passwd.xz passwd.Z [root@centos7 / testdir] # zip

Package the compressed file, and after being compressed by zip, it will generate a separate .zip file without deleting the original file.

Zip-package and compress (archive) files

-r: recursive processing that processes all files in the specified directory with subdirectories-Q: does not show the execution process

Unzip is used to decompress

Zcat is used to view

Use the example

[root@centos7 / testdir] # zip-Q passwd. / passwd [root@centos7 / testdir] # lspasswd passwd.bz2 passwd.gz passwd.xz passwd.Z passwd.zip [root@centos7 / testdir] #

Take a look at the general compression:

[root@centos7 / testdir] # lltotal 192 RW Murray. 1 root root 164065 Aug 19 09:06 message.zip-rw-r--r--. 1 root root 4129 Aug 19 08:46 passwd-rw-r--r--. 1 root root 1526 Aug 19 08:30 passwd.bz2-rw-r--r--. 1 root root 1539 Aug 19 08:39 passwd.gz-rw-r--r--. 1 root root 1540 Aug 19 08:45 passwd.xz-rw-r--r--. 1 root root 2151 Aug 19 08:16 passwd.Z-rw-r--r--. 1 root root 1676 Aug 19 09:02 passwd.zip [root@centos7 / testdir] # zcat

The zcat command views the compressed file, but does not extract it.

[root@bash ~] # zcat b.zipcircle http://yolynn.blog.51cto.com/tar binbash # write your 51cto blog URL in url, save the exit, run the script, and modify the zipper blog as needed.

The tar command creates an archive (backup file) of a file or directory, and the tar command packages many files into a single file, which can be archived and compressed in combination with compression tools.

Use syntax:

Tar [OPTION...] [FILE]... EXAMPLES tar-cf archive.tar foo bar # Create archive.tar from files foo and bar. Tar-tvf archive.tar # List all files in archive.tar verbosely. Tar-xf archive.tar # Extract all files from archive.tar.

Common parameters:

-c:-- creat, create a new backup file-C dir: extract-f:-- file=ARCHIVE in a specific directory, specify the backup file-x:-- extract,-- get, restore the file-t:-- list from the backup file, and list the contents of the backup file-v:-- verbose

Summary of tar usage:

(1) create an archive

Tar-c-f/PATH/TO/SOMEFILE.tar FILE...tar cf/PATH/TO/SOMEFILE.tar FILE...

(2) View the list of files in the archive file

Tar-t-f / PATH/TO/SOMEFILE.tar (3) expand and archive tar-x-f / PATH/TO/SOMEFILE.tartar-x-f / PATH/TO/SOMEFILE.tar-C / PATH/

(4) implement with compression tool: archive and compress

-j: bzip2,-z: gzip,-J: xz

Package it into a tar package:

Tar-cvf passwd.tar passwd packaged only, uncompressed tar-zcvf passwd.tar.gz passwd packaged and gzip compressed tar-jcvf passwd.tar.bz2 passwd packaged and bzip2 compressed tar-Jcvf passwd.tar.xz passwd packaged and xz compressed

Use the example

[root@centos7 / testdir] # tar-cf passwd.tar passwd [root@centos7 / testdir] # lspasswd passwd.tar [root@centos7 / testdir] # tar-zcf passwd.tar.gz passwd [root@centos7 / testdir] # lspasswd passwd.tar passwd.tar.gz [root@centos7 / testdir] # tar-jcf passwd.tar.bz2 passwd [root@centos7 / testdir] # lspasswd passwd.tar passwd.tar.bz2 passwd.tar.gz [root@centos7 / testdir] # tar-Jcf passwd.tar.xz passwd [root@ Centos7 / testdir] # lspasswd passwd.tar passwd.tar.bz2 passwd.tar.gz passwd.tar.xz [root@centos7 / testdir] # [root@centos7 / testdir] # tar-tvf passwd.tar # query-rw-r--r-- root/root 10240 2016-08-19 09:27 passwd [root@centos7 / testdir] # tar-tvf passwd.tar.gz-rw-r--r-- root/root 10240 2016-08-19 09:27 passwd [root@centos7 / Testdir] # [root@centos7 / testdir] # tar xf passwd.tar # decompress [root@centos7 / testdir] # lspasswd passwd.tar passwd.tar.bz2 passwd.tar.gz passwd.tar.xz [root@centos7 / testdir] # tar xf passwd.tar.gz [root@centos7 / testdir] # lspasswd passwd.tar passwd.tar.bz2 passwd.tar.gz passwd.tar.xz [root@centos7 / testdir] # [root@centos7 / testdir] # lltotal Murray. 1 root root 10240 Aug 19 09:27 passwd-rw-r--r--. 1 root root 20480 Aug 19 10:52 passwd.tar-rw-r--r--. 1 root root 116 Aug 19 10:53 passwd.tar.bz2-rw-r--r--. 1 root root 120 Aug 19 10:52 passwd.tar.gz-rw-r--r--. 1 root root 180 Aug 19 10:53 passwd.tar.xzcpio

The cpio command is a tool that packages and restores files through redirection. it can extract files that end in .cpio or .tar; in other words, cpio can copy files into or from an archive package.

Use syntax:

Cpio-copy files to and from archivescpio [options] > file name or device name cpio [options]

< 文件名或者设备名EXAMPLES% ls | cpio -ov >

Directory.cpio # must execute ls in the current working directory, followed by an error of% find. -print-depth | cpio-ov > tree.cpio% cpio-iv

< directory.cpio% cpio -idv < tree.cpio% find . -depth -print0 | cpio --null -pvd new-dir 常用参数： -o: --create,Run in copy-out mode,将文件拷贝打包成文件或者将文件输出到设备上-i: --extract,Run in copy-in mode,解包，将打包文件解压或将设备上的备份还原到系统-t: 预览，查看文件内容或者输出到设备上的文件内容-v: 显示打包过程中的文件名称。-d: 解包生成目录，在cpio还原时，自动的建立目录-c: 一种较新的存储方式 使用示例 [root@centos7 /]#find ./etc |cpio -o >

Etc.cpio # backup / etc directory wKiom1e3MfKArn2SAABJ8zL76mY046.png [root@centos7 / testdir] # find / etc/issue | cpio-o > issue.cpio1 block [root@centos7 / testdir] # lsissue.cpio [root@centos7 / testdir] # cpio-tv

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