The mv command can both rename and move files or folders.
Example: Rename directory A to B
mv AB
Example: Move the /a directory to /b and rename it to c
mv /a /b/c
In fact, to rename a file or directory in text mode, you only need to use the mv command. For example, to rename a file named abc to 1234:
mv abc 1234
Note that if there is also a 1234 file in the current directory, this file will overwrite it.