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1. Basic concepts:
Owner: General file creator, who created the file, it is natural to become the owner of the file
By [chown username] to modify the file's owner
When a user group creates a file, the file's group is the user is: where the group
By [chgrp group file name], modify the file's group
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2. User Management
useradd aaron add users
passwd aaron Change Password
Delete user userdel aaron
useradd aaron -m add users to simultaneously create the user's home directory
userdel aaron -r delete users delete the user's home directory
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3. User Group
groupadd group1 Add Group
groupdel group1 delete group
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4. add users to the group
Create a new user and add to the group
useradd -g group1 aaron add users to join the group at the same time
usermod -g group1 aaron change the user's group
usermod -g directory name aaron change the initial user login directory
The existing users to join group
gpasswd -a aaron group1 Users Group
gpasswd -d aaron group1 to remove the user from the group
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The user and group file
/ Etc / passwd to see all user information system
/ Etc / group to view all group information system
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6 , see the user details
finger Username
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7 , set up user profiles, input the user's profile
chfn user name (the system will interact with the model to improve the user's profile)
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8 , a user specified display command information
Including user ID, user name, number and the name of the primary group, affiliated group list
id username
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9, delete users and their personal folders
(Delete personal folders before adding -r)
userdel -r username
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Note: you can when using the useradd command by man or useradd --help to view information specific parameters, parameter using the parameter information required in accordance with.
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10 , common commands specific parameters
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Syntax: the usermod [parameters]
| -c <Notes> |
Modify user account callout text |
| -d <login directory> |
Modify directory when the user logs in |
| -e <expiration date> |
Modify the account expiration date |
| -f <buffer days> |
Modify the number of days after the password expires, ie close the account |
| -g <group> |
Modify the group the user belongs |
| -G <groups> |
Modify additional groups the user belongs |
| -l <account name> |
Modify the user account name |
| -L |
Lock user password, the password is invalid |
| -s<shell> |
After the shell is used to modify user login |
| -u<uid> |
Modify User ID |
| -U |
Password lock is released |
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Syntax: groupmod [parameters]
Common parameters:
| -g |
To use the setting group identifier |
| -O |
Reuse group ID |
| -n |
To use the setting group name |
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Syntax : chgrp [parameters] [directory]
Common parameters:
| -c |
Similar partially effective "-v" argument, but only in return change |
| -f |
No error message |
| -h |
Make changes to a file symbolic link, without any change to other relevant documents |
| -R |
Recursive processing, all files and subdirectories in the specified directory treated together |
| -v |
Display during execution of instructions |
| –reference |
The specified file or directory belongs to group all of their group and set to reference the same file or directory |
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Syntax: chown [parameters]
Common parameters:
| -R |
All files and subdirectories under the current directory of the same owner change |
| -c |
If the file owner really has changed, it shows the change action |
| -f |
If the document owner can not be changed and do not display an error message |
| -h |
Only changed files to link (link), rather than the real point of the link |
| -v |
Details show the owner to change the |
| –help |
Display HELP |
| –version |
Display version |
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Syntax: chmod [parameters] [file]
Common parameters:
| -c |
If the file permissions have changed indeed, it shows the change action |
| -f |
If the file permissions can not be changed nor display an error message |
| -v |
Details show permission to change the |
| -R |
All files and subdirectories in the current directory the same permissions changed (that is handed back to the way one by one to change) |
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Syntax: useradd [parameters] [username]
Common parameters:
| -D |
New user to change the preset value |
| -c |
Add notes text |
| -d |
When a new user home directory used by each landing |
| -e |
User termination date, the date format is YYYY-MM-DD |
| -f |
Users expired permanently suspended a few days. When the value is 0, the user is immediately suspended, and then turn this feature off value of -1, the default value of -1 |
| -g |
Specified user group corresponding to the user |
| -G |
This is defined as a member of a number of different user groups |
| -m |
Is automatically created when a user directory does not exist |
| -M |
Does not create the user's home directory, set file priority over /etc/login.defs |
| -n |
Cancel establish a user name in the name of the group |
| -r |
Establish a system account |
| -u |
Specifies the user id |
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Syntax: userdel [parameters] [username]
Common parameters:
| -f |
Forced to delete user accounts |
| -r |
Delete the user's home directory and any files |
| -h |
Displays help information about the command |
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Syntax : groupdel [parameters] [group name]
Common parameters :
| -h |
Displays help information |
| -R |
Apply the changes and use the configuration file chroot_dir directory in the directory chroot_dir |