cd command editing format:
/: Indicates the default directory file of cygwin installed on the computer itself
ls: You can list the list in a folder, enter the command and press Enter to display the file list
cd: change the current directory to another directory
cd -: Return to the directory where you entered this directory
cd ..: return to the parent directory
cd ../..: return to the previous two directories
cd / : / means to enter the root directory
cd /cygdrive: enter the cygdrive editing environment
cd+tab key: quickly find the folder