Commodore 128 System Manual page 196

CP/M 3.0 recognizes only correctly spelled command keywords.
If you make a typing error and press RETURN before correcting
your mistake, CP/M 3.0 repeats or " echoes" the command line,
followed by a question mark. For example, suppose you mistype
the DIR command, as in the following example:
CP/M replies with:
DJR?
This tells you that CP/M cannot find a command keyword spelled
DJR. To correct typing errors like this, you can use the INST/DEL
key to delete the incorrect letters. Another way to delete
characters is to hold down the CTRL key and press H to move
the cursor to the left. CP/M provides a number of other control
characters that help you edit command lines. Section 13 tells
how to use control characters to edit command lines and other
information you enter at your console.
DIR accepts a filename as a command tail. You can use DIR with
a filename to see if a specific file is on the disk. For example, to
check that the file program MYFILE is on your disk, type:
A>DIR MYFILE RETURN
CP/M 3.0 performs this task by displaying either the name of the
file you specified, or the message:
No File
Be sure you type at least one space after DIR to separate the
command keyword from the command tail. If you do not, CP/M
3.0 responds as follows:
A>DIRMYFILE RETURN
DIRMYFILE?
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