Linux

When we are working on a remote Linux server, if we want to know how many users on this server, how do we list them?

If we use ssh command to connect to remote server, but did not log out normally (for example, suddenly disconnected), when we enter next time, we may find that the server is full of our own usernames.

If you used ssh command to connect to the remote server, but you got the following error message causing you can not connect:

If we have a USB bootable flash drive when we reinstalling an operating system of computer, it is very convenient.

su is a very common command in Linux system, often used to switch users. At first I thought su was the abbreviation of switch user, but after searching, I discovered that it should be the abbreviation of substitute user.

If we got the following error message when we using sudo apt update command:

The installation steps of Pulse Secure on Windows and Mac OS are similar, but it may be more complicated on Linux, so this installation note is mainly based on the Linux system.

In the Linux operating system, it is sometimes difficult to find the interface for setting the second screen (after all, it depends on different distributions…). But sometimes, perhaps for the purpose of reporting, we may need to connect the computer to second screen.