Common commands in linux

1. file management commands mainly include ls, rm, mv, ln, mkdir, touch, cat & hellip; ls to view the file list. for example, to view the current directory: ls view the file list and display the file attributes, including time, group, and user. use: ls-l to sort by time: ls

1. file management

File management commands include ls, rm, mv, ln, mkdir, touch, cat ......

Ls to view the file list

For example, to view the current directory: ls

View the file list and display the file attributes, including time, group, and user. use: ls-l.

Sort by time: ls-lctr

View the files in the root directory: ls/

Rm delete File

For example, deleting a file f: rm f

Delete directory d: rm-r d

Mv mobile/renamed files

For example, change file name a to B: mv a B (note: If file B already exists, the previous file will be overwritten)

Move File a to the directory/temp: mv a/temp

Mkdir create Directory

For example, create Directory a: mkdir

Touch modify File time/generate new file

For example, generate a new empty file a: touch.

Modify file B to the current time: touch B

Cat output file content

For example, enter the config content of the file to the screen: cat config

2. Process Management

Ps: View system processes

For example, to view the process of the current user: ps

View all processes, including active and inactive: ps-ef

View all java processes: ps-ef | grep java

The second column is the process number.

Kill/killall terminate the process

For example, kill 300

Killall java

Bg/fg switch process to background/foreground

When a process runs in the current command line, you can press Ctrl + z to pause the process, and then use the bg command to switch the process to the background. On the contrary, you can use the fg command to switch the background process to the foreground, sometimes we use the & symbol to run the process on the background. This means we can use the fg command to switch it to the foreground.

View the process tree of the system

Run pstree to output the current process tree.

3. user management

Who view logged-in users

Adduser creates a new user for the system (root permission is required, the same below)

For example, add user james: adduser james.

Add user james, password 123456: add-p 123456 james

Passwd change user password

For example, if you change the password of james to 888888: passwd james, the system prompts you to enter the old password and then enter the new password.

Userdel delete user

For example, delete user james: userdel james.

Usermod modify user attributes

For example, modify james to the admin group: usermod-p admin james.

4. resource management

Top view system resource status

Top is the most commonly used tool to view the current status of the system. You can view CPU, memory, load, etc.

View host CPU information

Run cat/proc/cpuinfo

Query System memory information

Run cat/proc/meminfo

Fdisk view hard disk partitions

Fdisk-l/dev/sda can output the list of hard disk/dev/sda partitions.

Df view in-use file system

Run df-h

Hdparm view hard disk information

For example, you can view the hda speed of a hard disk and run hdparm-I/dev/hda.

Query usb interface information

Run the command lsusb to know how many usb interfaces the current system has.