Linux Three week First Class (April 2) linux,windows cross-file user profile Password group management

Three week First Class (April 2)

2.27linux and Windows inter-pass files
3.1 User profile and password configuration files
3.2 User Group Management
3.3 User Management

Linux and Windows file transfer

I usually use FTP or other file management methods.

Here's a way to do this, but you can only use it under Xshell, install the Lrzsz kit

After installation, you can use the SZ command + files to transfer

If you want to transfer from Windows to Linux, you can use the RZ command

Overall summary

You can use Xshell SECURECRT cannot use putty

Install the Lrzsz tool and use SZ to pass it to Windows with RZ from Windows to Linux

Next is to learn the content of users and groups

/ETC/PASSWD is the user's configuration file

Used: 7 segments were divided

The user you created is a 1000uid start root is 0

The third paragraph is the user ID UID

The fourth segment is the group ID GID

The second paragraph is x, the early release of the code, and then found it. It's so easy to find, it's in the shadow.

The fifth paragraph is the annotation information, does not have the actual function

The sixth paragraph is the user's home directory

The last paragraph is that the user's shell user must have a terminal to interact with, the shell is such a terminal, its position is the last paragraph.

The real secret is

/etc/shadow passwords are stored in the same order as user profile one by one

A total of 9 paragraphs, name: Password: Days (1970.1.1 to the time of the password change)

"If you want to make two commands on one line, you can connect them with semicolons."

Shadow the meaning of each field can be understood

Next up is the group file

Etc/group file is a group configuration file, which means the name of the password ID, the structure with the user very much, the password stored in the/etc/gshadow

/etc/shadow-/  /etc/shadow/    /etc/passwd /etc/passwd-    /etc/gshadow  /etc/gshadow-/  files behind the belt-, the system automatically for us to back up, accidentally deleted, can be copied back, but there may be a new user just not updated in time to cause loss.

New group Groupadd group name can also be customized GroupID starting from 1000 groupadd-g GID group name

Delete Group Groupdel group name Remember that the group cannot be deleted when it is not empty

User Management

Useradd adding users

Add user has option optional

-U UID

-G GID

-D Specify home directory

-S Specify shell

-M create user but do not create home directory

Userdel username Deletes the user directly, but retains the home directory because it is not sure if there is an important file root user can use

-r option to delete home directories

After deletion, the default is to keep the home directory/etc/passwd no user information

Linux Three week First Class (April 2) linux,windows cross-file user profile Password group management