Each variable has a number of attributes, including:
Some system variable names begin with ‘$’, but user-defined variables' names may not begin with ‘$’.
The final character in a variable name should not be ‘.’, because
such an identifier will be misinterpreted when it is the final token
on a line: FOO.
will be divided into two separate tokens,
‘FOO’ and ‘.’, indicating end-of-command. See Tokens.
The final character in a variable name should not be ‘_’, because some such identifiers are used for special purposes by pspp procedures.
As with all pspp identifiers, variable names are not case-sensitive. pspp capitalizes variable names on output the same way they were capitalized at their point of definition in the input.
DISPLAY
can be used to show this order: see DISPLAY.
WRITE
command
(see WRITE).