/sys$common/syshlp/helplib.hlb READ, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 logical-name[:]

    Specifies the logical name of the input file from which a record
    is to be read. Use the logical name assigned by the OPEN command
    when the file was opened. (The OPEN command assigns a logical
    name to a file and places the name in the process logical name
    table.)

    In addition, you can specify the process-permanent files
    identified by the logical names SYS$INPUT, SYS$OUTPUT, SYS$ERROR,
    and SYS$COMMAND.

 symbol-name

    Specifies the name of a symbol to be equated to the contents of
    the record. The name must be 1 to 255 alphanumeric characters and
    must start with an alphabetic letter, an underscore (_),  or a
    dollar sign ($).

    When you specify a symbol name for the READ command, the command
    interpreter places the symbol name in the local symbol table
    for the current command level. If the symbol has already been
    defined, the READ command redefines it to the new value being
    read.