Suppose you're typing a command line query into a MySQL database and you need to cancel out and start over. From a bash shell you could just type ctrl-c and get a new prompt. In MySQL, ctrl-c would exit the client and return you to the shell.
For example, I have a long, complex SELECT statement typed in but I haven't yet hit return. I realize that I don't want to send the command but I want to have the command on-screen so I can use it as a reference. I'd like to bail out without quitting MySQL. Any ideas?
Key point: the command hasn't yet been executed.
When you start up MySQL, you'll likely see this message:
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
The "buffer" that it's referring to is the command/query buffer.