0003_common commands for Linux and 0003_common commands for Linux

0003_common commands for Linux and 0003_common commands for Linux

1. pwd: view the current directory

2. cd: Switch Directories

3. ls: view the files and folders in the current directory:

4. ls-l: list the files and details in the current directory. If the first character of drwxr-xr-x is d, it indicates the directory.

The ls-lh file size is 1 kb = 1024 bytes, 1 Byte = 8 Bits (BIT), and 1 bit indicates a state.

Ls-a shows hidden files.

Vim. test: Create a hidden file named test.

5. cd ..: Return to the directory of the upper-level

Cd ../back to Layer 4 directory

6. Create a file with the vim file name

I. edit files

After writing the file, Press ESC to exit the editing mode, press shift +:, and then press wq (write + quit) to save the file and exit.

7. view the file content with the cat file name

Vim file name View File Content

For more file names, view the file content slowly. Press enter and press Enter. For the next page, Press space.

 

8. Create a folder:

Mkdir directory name create directory name

Mkdir-p/etc/temp/1/2/3/4 recursion layer-by-layer creation of multi-level Directories

9. Run the "cd root --> yum-y install tree" command to view the directory structure of CN in tree CN.

10. Move music videos

11. Copy files using cp

12. rm delete the file. Rm-rf force delete files and folders

13. man view online help documentation

14. help view the Linux built-in command help

15. -- h simple view of help

16. find: find/-name * caixin *

Find/-size + 90 M | xargs ls-lh searches for files, MPs queues | and xargs use the preceding command execution result as the subsequent input.

17. Create a file using the touch path name

18. df-h view disk status

19. view the process running status in ps

20. kill pid to close the process, and kill-9 pid to force the process to close

21.> directory name: Clear the content in the file

22. grep keyword file name: captures a line of text with a keyword in the file.

23. vim install. log + 505: Jump to the 505th line of the install log file.

24. tar zcvf demo.tar.gz./*: Pack all files in the current directory.

25. sz file name: download the file to the specified directory of Xshell. If no sz command is prompted, su root --> yum-y install lrzsz

26. du: view the file (directory) Size

27. free-m view Server Memory in MB

28. top dynamically displays the CPU or memory usage of processes (htop)

Cpu: us (user): CPU occupied by user processes

Sy (system): CPU occupied by the system itself

Id (idle): CPU idle rate

Wa (I/o wait): time ratio of CPU wait for I/O

Mem: total used free buffers (buffer zone, ready for use) total free (available memory) = free + cached + buffers total usage (used) = total-total free

Swap: total used free cached (cache)

29. chown user (owner). user group (group) Directory: chown root. root test/change the group of the test directory to root

30. rwxr-xr-x: a group of three letters. The first is user permissions, the second is user group permissions, and the third is other user permissions.

R read 4

W write 2

X excute 1

-0

Then rwx r-x:

4 + 2 + 1 4 + 1 4 + 1

Rwxrwxrwx is 777: rwx

4 + 2 + 1 4 + 2 + 1 4 + 2 + 1

Change File Permission: chmod 755 test/755 is the security permission

31. SEARCH Command Parameter usage: man find -->/size to view the size usage of find

 

 

Overall:

Online query and help (2): man, help

File and directory operations (19): ls cd cp find mkdir mv pwd rename rm rmdir touch tree basename dirname chattr lsattr file md5sum

Command for viewing files and content processing (19): cat tac more less head tail cut split paste sort uniq wc iconv dos2unix file diff vimdiff

Rev grep egrep join tr vi/vim

File compression and decompression command (4): tar unzip gzip

Information Display command (12): uname hostname dmesg uptime file stat du df top free date cal

Search FILE command (4): which whereis find locate

User management command (10): useradd usermod userdel groupadd passwd chage id su has do sudo

Basic Network Operation Command (10): telnet ssh scp wget ping route ifconfig ifup ifdown netstat

In-depth Network Operation Command (6): nmap lsof route mail mutt nslookup dig host traceroute tcpdump

Commands for disks and file systems (10): mount umount df du fsck dd dumpe2fs dump fdisk parted mkfs partprobe

E2fsck mkswap swapon sync resize2fs

Command for shutdown and Viewing System Information (3): shutdown halt init

System Management commands (8): uptime top free vmstat mpstat iostat sar (sysstats) chkconfig

System security commands (10): chmod (modify file permissions) chown (modify file group) chgrp chage passwd su sudo umask chattr lsattr

Command for viewing system user logon information (7): whoami who w last lastlog users finger

Others (19): echo printf rpm yum watch alias unalias date clear history eject time nohup nc xargs exec export unset type bc

Advanced System Performance Monitoring command (12 ):

Memory: top free vmstat mpstat iostat sar

CPU: top vmstat mpstat iostat sar

I/O: vmstat mpstat iostat sar

Process: ipcs ipcrm lsof strace lstrace

Load: uptime

Shutdown/restart/logout command (7 ):

Shutdown and restart: shutdown init halt poweroff reboot

Logout: logout exit ctl + d

Process Management (16 ):

Bg: Running fg in the background: suspending the program jobs: displaying the background program kill, killall, pkill: killing the process

Crontab: Set scheduled ps: view process pstree: Display Process status tree

Top: Display process nice: Change Priority nohup: the user continues to work after exiting the system

Pgrep: Find the matching process strace: trace the system call of a process

Ltrace: trace the details of the function called by the process. vmstat: reports the virtual memory statistics.

Runlevel init service

Very dangerous system commands (5 ):

Mv rm fdisk parted dd