CentOS File Rights Management

Refer to Bird's private cuisine: http://vbird.dic.ksu.edu.tw/

First of all, a comparison of the pit: I used the company's FTP server A few days ago, the hands of the root directory to execute a bit of code

sudo chmod 777/-R

Duang, the system has collapsed. Root can't go in, all kinds of problems follow, remedial method tried a lot, but not all. Finally reluctantly reinstall the system. Fortunately, there is nothing important.

The cause of this problem: the rights management of the file smattering, only know that set 777 permissions, you can rest assured that the use. The final result is the error of non-operation. Can only say that smattering killed people, the Apprentice not fine pit dead.

The landlord to set the thinking, so re-learn the permissions of the file management this together.

The first command for Rights management:

CHGRP//Set permissions for groups Chown//set permissions for users and groups chmod//set Read and write execution permissions

Check the permissions of the files in the/root directory first:

[Email protected] ~]# ls-ll install.log-rw-r--r--. 1 root root 37332 November 21:11 Install.log printing Information The first part:-rw-r--r--//1th bit represents the file type, here is the normal file, if it is D, if it represents the directory, if L is the link 2-4 bits, indicating the permissions of the user who owns the file , here rw-, indicating that the owning user has read and write permissions 5-7 bits, representing the permissions of the group to which the file belongs, where R--, indicates that the owning group has read-only permission 8-10 bits, which represents the permissions of users and groups other than users and groups, where R--, indicates that other users and groups have read-only permission to do so: type User group other type users other part two: 1 means that the document link node has 1 third parts: root root indicates that the user of the file is root, and the group belongs to root Part IV: 37332 means the file size is 37332 bytes Part V: November 30 21:11 indicates time Part VI: Install.log represents the full format of file name files information: File type file permissions file link node belongs to user group file size last Edited time file name

To change permissions by using the Rights Management command:

Chgrp change file belongs to group: [[email protected] ~]# CHGRP test install.log[[email protected] ~]# ls-ll install.log-rw-r--r--. 1 root test 37332 November the 21:11 install.log file belongs to the group test, so members of the test group have read permissions to the Install.log file.

Chown change the user to which the file belongs:

[Email protected] ~]# chown test install.log[[email protected] ~]# ls-ll install.log-rw-r--r--. 1 test test 37332 November 21:11 install.log file belongs to Test.test user has read and write permission to Install.log file

Chown changing users and groups at the same time:

[Email protected] ~]# chown root:root install.log[[email protected] ~]# ls-ll install.log-rw-r--r--. 1 root root 37332 November 21:11 install.log by execution, chown user:group filename simultaneously changes users and groups

chmod changing permissions for a file

R stands for file readable, W stands for file writable, X stands for executable chmod  command format for file:     chmod u=rwx,g=rwx,o=rwx filename  //u represents the user, G represents the group, and O indicates the other     chmod +x filename               //Add executable Permissions     chmod -x  filename              //minus executable permissions [[email  protected] ~]# ls -ll install.log-rw-r--r--.  1 root root 37332  11 Month  30 21:11 install.log[[email protected] ~]# chmod u+x,g+x,o+x  install.log[[email protected] ~]# ls -ll install.log-rwxr-xr-x. 1  Root root 37332 11 month  30 21:11 install.log//increased, executable permissions [[email protected]  ~]# chmod -x install.log[[email protected] ~]# ls -ll  Install.log-rw-r--r--.  1 root rooT 37332 11 Month  30 21:11 install.log//Reduced executable permissions to change permissions digitally:rwx  4,2,1, 4+2+1 =  7 //All rights 4+2 = 6 //readable, writable 4 + 1 = 5 //readable, executable 2 + 1  = 3 //writable executable chmod 777 filename //user, group, others are readable, writable, can execute Chmod 755 filename  //user readable, writable, executable, group and other readable, enforceable [[Email protected] ~]# chmod 777 install.log[[email  protected] ~]# ls -ll install.log-rwxrwxrwx. 1 root root 37332  11 Month  30 21:11 install.log//Restore original permissions [[email protected] ~]# chmod 644  install.log[[email protected] ~]# ls -ll install.log-rw-r--r--.  1  Root root 37332 11 month  30 21:11 install.log file and directory permissions feature differences:file  rwx    //read-Write execution R     represents the contents of a file that can be read and written W write     can edit, add, or modify the contents of the file (but not delete it) x execute   The file can be executed as a binary file, just have such permission, the execution is successful, to see the file insideCapacity dir   rwx   //read and write execution r  representative can read and write the contents of a file w  create new files and directories    Delete existing files and directories    change the name of the file or directory    move the file or directory to another directory x  representative can access the file

CentOS file Rights Management