Due to the impact of the epidemic (hope to get better soon), I can only work from home and install the development environment again.
Use apt-get install to encounter the following problems
1.sudo apt-get update update software source
If the update is successful, there is no error, no warning, just execute your own download
But there is a warning at the end of my execution
Some index files failed to download. They have been ignored, or old ones used instead.
After querying the data, I found that it was my own update source problem. You need to switch the update source and perform the following steps
2. Search and open software&update
Select after opening
Choose other
After changing the source, execute sudo apt-get update, no error is reported, and then download what you need to download
It may be a problem with the Ubuntu downloaded this time, which caused this problem. I have never encountered it before.