Linux Basic Instruction III

1. chmod
   

Function: Change the permissions of the file.

Syntax: chmod [-r] XYZ file or directory (numeric type changes file permissions)

XYZ: is the permission attribute of the number type just mentioned, which is the sum of the numeric values of the Rwx property.

-R: Continuous improvement of recursion, that is, all files under subdirectories will change.

Example: Chmod-r 777 Testfile

Modify the directory Testfile and all the users in the directory have full permissions.

Syntax: chmod U + (join) R

G-(remove) W file or directory

o = (set) x

A

Example: chmod g+w testfile

Gives the file testfile the group write permission.

2.chown

Function: Change file or directory owner

Syntax: chown [User: User group] [file or directory]

Example: Chown root:root Install.log

3.chgrp

Function: Change the owning group of a file or directory

Syntax: chgrp [user Group] [file or directory]

Example: Chgrp users Install.log

4.gzip

Features: Only files can be compressed and directories cannot be compressed. After compressing only the compressed package, the source file is missing and the source file is not preserved.

Syntax: gzip [-cdtv#] file name. gz

-C: The compressed data is sent to the screen, can be processed by data stream redirection;

-D: the extracted parameters;

-T: can be used to verify the consistency of a compressed file, to see whether the file error;

-V: can display the original file/compressed file compression ratio and other information;

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

Example: Gzip-v man.config

5.tar

Function: Package directory. All users have Execute permissions. Format after compression: tar.gz

Syntax: tar option [-zcf][compressed file name] [directory]

TAR-C: Packing

TAR-V: Show more information

Tar-f: Specify file name

Tar-z: Packing and compressing at the same time

Example: Tar-zpcv-f/root/etc.tar.gz/etc

The tar Command decompression command:

Tar-x: Unpacking the Package

TAR-V: Show more information

Tar-f: Specify Unzip file

Tar-z: Decompression

Example: TAR-ZXVF japan.tar.gz

6.zip

Features: Compress files or directories. Compressed format:. zip. Compressed files and original files after compression.

Syntax: Zip option [-r] [compressed post file name] [file or directory]

Example:

7.unzip

Function: Unzip compressed file of. zip

Syntax: Unzip [compressed file]

Example: Unzip Test.zip

8.bzip2

function: To replace gzip, provide a better compression ratio.

Syntax: bzip [-cdkzv#] File name

-C: The data in the compression process is output to the screen;

-D: the extracted parameters;

-K: retains the original file without deleting the original file;

-Z: Compressed parameters

-V: can show the source file/compressed file compression ratio and other information

-#: Same as gzip, all in the calculation of compression ratio parameters,-9 best,-1 fastest.

Example: Compressing/tmp/man.config with bzip2

Bzip2-z Man.config

9.bzcat

Function: Unzip the specified. bz2 file and display the extracted file contents. The original compressed file is preserved and the extracted files are not generated.

Syntax: bzcat [. bz2 Compressed file: Specifies the. bz2 compressed file to display content. ]

Example: Compress/tmp/man.config in bzip format:

Bzip2-z Man.config

10.compress

[[email protected] ~]# compress [-DCR] file or directory

Parameters:

-D: Parameters to decompress

-R: can also be compressed together with the files in the directory!

-C: Output compressed data to standard output (outputs to screen)

Example:

Example one:/etc/man.config is copied to/TMP and compressed

[Email protected] ~]# cd/tmp

[Email protected] tmp]# cp/etc/man.config.

[Email protected] tmp]# compress man.config

[Email protected] tmp]# ls-l

-rw-r--r--1 root root 2605 Jul 11:43man.config.z

Example two: Unlock the zip file you just got

[Email protected] tmp]# compress-d man.config.z

Example three: compressing the man.config into another file to back up

[Email protected] tmp]# compress-c man.config >man.config.back.z

[email protected] tmp]# ll man.config*

-rw-r--r--1 root root 4506 Jul 11:43man.config

-rw-r--r--1 root root 2605 Jul 11:46man.config.back.z

# The parameters of this-C are more interesting! He will output the data from the compression process to the screen instead of writing it into

# file. Z file. Therefore, we can export the data to another file name through a data flow redirection method.

# for Data flow redirection, we'll talk more about it in bash shell!

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Linux Basic Instruction III