If, while entering a command, you realize that you forgot the full command
syntax or want to check
something else, a mechanism has been introduced to let you interrupt
the command line, execute another command or commands, and then resume
with the interrupted line.
To interrupt a command line enter `
' (back--slash) as the
last character
and hit 
.
The command string is then saved internally. To resume entering the
interrupted command line,
type `
' (back--slash) again followed by 
. The saved
command line will be displayed on the terminal and you may add more input.
Note cannot edit or change the saved portion of the command after reentering the interrupted string, since your new input is handled as if it were a continuation of the original command line.