Summary and use of compression tools under Linux (see Private dishes)

1 compression

gzip command

Options

-C Data Flow redirection, which can be positioned as a file

-R recursive compression, that is, deep sub-directory

-V displays redundant information such as name and compression ratio

-D Decompression

-# plus the number indicates the compression level, the higher the compression ratio, but the slower

① did a very simple experiment.

[Email protected] tmp]# ll-htotal 128k-rw-r--r--. 1 root root 128K June 03:00 Test[[email protected] tmp]# gzip-v-9 testtest:99.9%--Replaced with Test.gz[[email prot Ected] tmp]# ll-htotal 4.0k-rw-r--r--. 1 root root 166 June 03:00 Test.gz[[email protected] tmp]# gzip-d test.gz [[email protected] tmp]# gzip-v-1 test test : 99.6%--Replaced with test.gz

② How to keep the original file?

A solution I think is very useful, above the-C command

[[email protected] tmp]# gzip-c Test > Test.gz[[email protected] tmp]# lltotal 132-rw-r--r--. 1 root root 131072 June 03:00 Test-rw-r--r--. 1 root root 166 June 03:03 test.gz

④ use Zcat can read the compressed file directly, if the cat can read the original file, so called Zcat = =

[Email protected] tmp]# Zcat test1.sh.gz This is a test.

bzip2 command

It is said that there is a better compression ratio than zip, the command line is used, it is recommended to use similar sub-options

Did a simple little experiment.

[[email protected] tmp]# gzip-9-v-c test >test.gztest:99.9%[[email protected] tmp]# bzip2-9-v-c test >test.bz 2 test:2978.909:1, 0.003 bits/byte, 99.97% saved, 131072 in,.

Sure enough, other uses similar, not recommended to continue to try

Bzcat is the same.

[Email protected] tmp]# Bzcat test1.sh.bz2 This is a test.

Let's see how to package and compress the unpacked package.

Tar command

There's a section on the Internet that's good, take it off here

Parameters:
- C: Create a compressed file parameter directive (the meaning of Create);
-x: Unlock the parameter instructions for a compressed file!
-T: View the files inside the Tarfile!
in particular, in the release of the parameters, c/x/t can only exist one! Cannot exist at the same time! Because it is not possible to compress and decompress simultaneously.
-Z: Do you have the properties of gzip at the same time? i.e. do I need gzip compression?
-j: Do you have bzip2 properties at the same time? i.e. is it necessary to compress with bzip2?
-V: Files are displayed during compression! This is commonly used, but is not recommended for use in the background execution process!
- F: Use the file name, please note, after F to immediately answer the file name Oh! Don't add any more arguments!
For example, the use of "TAR-ZCVFP tfile sfile" is the wrong way of writing, to write "TAR-ZCVPF tfile sfile" to Oh!
- P: Use original file properties (attributes are not changed according to user)
- P: You can use absolute path to compress! This is convenient for configuration files, general backup/etc Best Use-P

-N: Newer than next date (YYYY/MM/DD) will be packaged in the new file!
--exclude file: In the process of compression, do not package file!

-C directory Specifies the extracted directory

Basically the usual ones have been explained

Note the following points

1 Tar practical time to consider, of course, is compressed, then consider the use of zip or bzip,zip using Z,bzip J, unzip the same

2-f is followed by the file, so F is immediately followed by the compressed file to be created, and then the source file to be compressed

Let's keep doing our little experiment.

① package tmp with all except test files to the/root/backup/directory, using BZIP2 compression

[Email protected] tmp]# tar-jcvf/root/backup/tmp.bz2/tmp--exclude testtar:removing leading '/' from member Names/tm p//tmp/test.bz2/tmp/test.gz/tmp/test1.sh.bz2

② at this time required to retain the file attributes, the/ETC/MY.CNF compressed into/root/backup/directory, the name asked My.bak

[Email protected] tmp]# tar-jcvpf/root/backup/my.bak/etc/my.cnftar:removing leading '/' from member NAMES/ETC/MY.CNF

③ in the root home directory, the file is later than July 11, 2015 backup, named 2015.7.11.bak

[Email protected] ~]# tar-jcvp-f/root/backup/2015.7.11.bak/root-n 20150711

④ Add a file/tmp/test in the ③ compressed file and view

[Email protected] ~]# tar-rf/root/backup/2015.7.11.bak.tar/tmp/testtar:cannot Update compressed Archivestar:error Is isn't recoverable:exiting now

Added a half day, found this error, just realize that I have been compressed to this, so the best way is to re-compress, of course, for a tar package to add re-compression can also

[Email protected] ~]# tar-jcvpf/root/backup/2015.7.11.bak/tmp/test/root-n 20150711[[email protected] ~]# TAR-TVF /root/backup/2015.7.11.bak

Or so

[Email protected] ~]# tar-cf/root/backup/2015.7.11.bak/root[[email protected] ~]# Tar-rvf/root/backup/2015.7.11.bak /tmp/test tar:removing leading '/' from member Names/tmp/test[[email protected] ~]# Tar-tvf/root/backup/2015.7.11.bak ...-rw-r--r--root/root 131072 2015-06-27 04:27 tmp/test

In short, the other is to use it later, of course, the front can also not apply-, such as the tar XF, this is another style, Big day I also forgot

This article is from the "Learning Path of Kai Learning" blog, please make sure to keep this source http://qixue.blog.51cto.com/7213178/1673917

Summary and use of compression tools under Linux (see Private dishes)