LInux Hotkey Memo

Recently learning embedded in a classic operating system Linux, for some hotkey memo here.

Tab: Command completion, file path completion

CTRL + C: terminating a running program
Ctrl+d: Introducing the character interface

Linux is a multi-user operating system. User information can be found in etc/passwd
A row of records in/etc/passwd corresponds to a user

Each record is then separated by a colon: 7 fields, meaning the following:
• User Name
• Passwords (usually replaced by X, actual passwords in/etc/shadow
UID (user identifier: number)
UID (user identifier: number)
GID (the group where the user resides)
• Full user name
• User home Directory
• The command parser used by the user

User and user groups: UID determines the type of user
1. System administrator (Root): A user with all rights to the system,
Its uid is 0.
2. Ordinary users: That is, the general user, the use of the system has limited access to its
The UID is between 500-60000.
3. System users: Protect the system operation of users, generally do not provide password login
System with a UID of 1-499.

Grouping users is a means by which Linux systems manage and control access to users, each of which belongs to a group of users, a group can have multiple users, and a user can belong to a different group.

Many of the information in the user group is stored in the Etc/group file, and the format is separated into several fields by ":".
1) "Group name" is the name of the user group and the group name should not be duplicated.
2) password for the "password" user group. User groups generally do not have passwords.
2) password for the "password" user group. User groups generally do not have passwords.
3) The "group ID" is similar to the user identification number and is also an integer.
4) "Group user list" is a list of all users belonging to this group,
separated by commas (,) between different users.

File properties:-rwxr-x-wx
'-': ordinary file; r: readable; w: writable; x: Executable

LInux Hotkey Memo