5 to Linux-compression and backup, 5 to linux

5 to Linux-compression and backup, 5 to linux

I. Common compressed files in Linux

*. Z compress compressed files (not popular now, and can be decompressed using gzip );

*. Files compressed by the gz gzip program;

*. Bz2 bzip2 compressed files;

* The data packaged by the. tar program has not been compressed;

* .Tar.gz tar package files, which are compressed by gzip

* .Tar.bz2 tar package files, which are compressed by bzip2

 

Ii. Common compression commands

1. gzip compressed to gzip

Gzip [-cdtv #] File Name

Options and parameters:

-C: outputs compressed data to the screen and can be processed through data stream redirection;

-D: extract parameters;

-T: it can be used to check the consistency of a compressed file and check whether the file has any errors;

-V: displays the compression ratio of the original file/compressed file;

-#: Compression level.-1 is the fastest, but the compression ratio is the worst.-9 is the slowest, but the compression ratio is the best! The default value is-6.

 

2. zcat file name .gz

Directly view the File Content Without decompression

 

3. bzip2 compressed to bzip2

Bzip2 [-cdkzv #] File Name

Options and parameters:

-C: output the data generated during the compression process to the screen!

-D: extracted Parameters

-K: Keep the source file without deleting the original file.

-Z: Compression Parameters

-V: displays the compression ratio of the original file/compressed file;

-#: Compression level,-9 is the best,-1 is the fastest!

 

4. bzcat file name .bz2

Directly view the File Content Without decompression

 

5. tar packaging command

Options and parameters:

-C: Create a package file

-T: Check the file names contained in the package.

-X: unpack or decompress the package. You can use-C to uncompress the package in a specific directory.

-J: Use bzip2 to compress or decompress the file. The file name is * .tar.bz2.

-Z: compression/Decompression using gzip support: the file name should be * .tar.gz.

-V: displays the file name being processed during compression/decompression!

-F filename: name of the file to be processed immediately after-f! -F is recommended to write an option separately!

-C Directory: This option is used for decompression. to decompress the package in a specific directory, you can use this option to select "Unzip.

-P: retains the original permissions and attributes of backup data. It is often used in backup (-c) important configuration files.

-P: retain the absolute path, that is, allow the backup data to contain the root directory;

-- Exclude = FILE: do not pack the FILE during compression!

 

Use Case:

Compression: name of the file or directory to be compressed by tar-jcv-f filename.tar.bz2
Query: tar-jtv-f filename.tar.bz2
Decompress: tar-jxv-f filename.tar.bz2-C directory to be decompressed

Extract only a specific file: tar-jxv-f/root/etc.tar.bz2 etc/shadow

 

Iii. System Backup and Restoration

1. You can use dump to back up the file system.

Dump supports the backup of the entire file system or a single directory. When backing up a single file system, you can perform hierarchical backup. During backup, you can use a mount point or device file name.

When you back up a directory, all the backup data must be under this directory. Only full backup is supported and hierarchical backup is not supported.

 

Dump [-Suvj] [-level] [-f backup file] data to be backed up

Options and parameters:

-S: only list the disk space required for data backup;

-U: record the dump time to the/etc/dumpdates file;

-V: displays the dump file process;

-J: added support for bzip2! Compress data. The default bzip2 compression level is 2.

-Level: the level from-0 ~ -9 a total of 10 levels;

-F: A bit similar to tar. The files subsequently generated can also be connected to/dev/st0 device file names.

-W: Have dump-Set partition backups been listed in/etc/fstab?

 

2. Use restore to restore the system.