Indicates that everything that follows it on a command line is a
comment and should not be processed as part of a command.
Format
!
Example
$ !
$ WRITE SYS$OUTPUT "hello" ! This command should output "hello".
hello
$ FOO = " " ! This command defines FOO as a blank.
$ FOO WRITE SYS$OUTPUT "hello" ! This command should output "hello".
hello
$ FOO = "!" ! This command defines FOO as a !.
$ FOO WRITE SYS$OUTPUT "hello" ! This command should be ignored.
$
