Some useful Linux Command tools

I just saw a series of blog posts about commands that are rarely used but are very useful at ordinary times. I chose some of the commands that I think should be used to write notes.

Some of these commands are not system commands. You need to download and install them on your own. Debian installation:Sudo apt-get install XXXX. RHEL installation:Yum install XXXX.

1. mtr, with both ping and traceroute commands:

For example, to track the trend of data packets sent to www.baidu.com, a dialog box is displayed on the visual interface:

Mtr www.baidu.com

It can be seen that the displayed data is complete, including the packet loss rate, and the last hop is 115.239.209.10. This address is correct.

2. Ctrl + x + e

When the terminal is enabled, press ctrl + x + e to enter the text mode immediately. Press ctrl + x after you enter the text to play and save it. (All options are displayed ), finally, enter the Save path and file name, which are saved in the/tmp folder by default:

3. ss command:

Ss indicates socket statistics. This command is similar to the netstat command and displays TCP connection information:

4. last command:

The last command displays the user logon and logout history, which is from the/var/log/wtmp file.

5. tree Command:

6. pstree command, process tree:

7. Run the history command to view the command history:

The history command can view the history of input commands. It seems to be saved as a constant string, so only one of the same commands will be saved:

8. Run the stat command to list the details of the file:

This command can detail the information of a file, such as the size, permission, last access time, and last modification time. It is also a practical command.

9. pv command and fun print command:

When hackers knock on the code in a movie, do they feel special? The code is printed slowly, and the pv command can be done. Although it is really useless, it should be installed with apt-get or yum first, then enter the following command to test

Echo "This is just a simple test. The text content is printed one by one on the terminal." | pv-qL 20

10. mount | column-t command combination to display the current mount list:

This command combination can display the list of currently mounted file systems:

11. Press ctrl + l to clear the terminal display content:

We can also use the clear command to clear the terminal display content, but ctrl + l is much more convenient.

12. file command:

The file command also tells you the file encoding method:

13. The id command gets the id information of the user (Group:

This command lists the detailed id information, but does not know how to use this id information for the moment:

14. Run the at command regularly:

This command is similar to the cron command. It executes USER commands at a specified time, for example:

Echo "ls-l>/dev/pts/0" | at or echo "ls-l>/dev/pts/0" | at PM

This means that the detailed information in the folder is written into the/dev/pts/0 file at the specified time. The ">" symbol can be added with the output content to the specified file.

15. du-h -- max-depth = n command:

This command outputs the size of the sub-folder under the current directory (n specifies the maximum number of recursion layers) to the terminal in a unit, such as (comparing ls-l ):

16. Run the look command to blur the spelling of English words:

If you are not sure whether the English words you entered are in this fight, Baidu and google can be the most direct. Of course, the Linux system comes with a fuzzy check tool, for example, I want to spell difficult, but I don't know, right? If you enter look diffi in a fuzzy way, it will give you the answer:

17. factor command, factorization:

18. The tac command outputs the file content in reverse order:

Very talented, cat is the tac. After the command is completed, the text content is output in reverse order:

19. Run the disown-a & exit command to run the process in the background:

Generally, we open a terminal to execute a command. If the terminal is closed, the process will end. However, if the disown-a & exit command is used, the process can be closed after the terminal is closed, it can still be run in the background in the format:

20. convert command. The output terminal result is of the specified file type:

For example, I want to output the structure tree of the specified folder as a png Image:

The question mark is a Chinese character and cannot be identified or garbled.

21. Run the host and dig commands to find the available IP addresses of the specified host:

For example, to find the IP address of Google DNS, run the host command:

The dig command is more detailed:

22. dstat, system resource monitoring:

This command dynamically updates and displays system information. You can use the corresponding process ID to determine the resource usage:

23. Run the nc-zv command to check whether the port is Enabled:

Command usage:

Nc-zv host name or address port number

For example, I want to know the port 80 of www.baidu.com:

Change the local port to localhost or 127.0.0.1.

24. Run the pdftk command to merge multiple pdf files:

Command usage:

25. The ps-LF-u user_name command displays the process information executed by the specified user: