command-line
Specifies a command line to start a particular editor on your
system when you use the EDIT command.
You need not specify a command line if you use /CALLABLE_EDT,
/CALLABLE_LSEDIT, or /CALLABLE_TPU. If you do not use one of
these qualifiers, the editor specified in the SET EDITOR command
line is spawned to a subprocess when you enter the EDIT command.
You can specify a command line with /CALLABLE_LSEDIT or
/CALLABLE_TPU but not with /CALLABLE_EDT.