2.5.2.2 ASSIGN Command
  The ASSIGN command equates a logical name to a complete
  file specification, a device, or another logical name.

  If the logical name translates to a device name and is used
  in place of a device name in a file specification, end the
  equivalence name with a colon.

  The following example uses the ASSIGN command to make
  the system HELP library available from within BASIC:
  Ready
  ASSIGN SYS$HELP:HELPLIB HLP$LIBRARY

  The ASSIGN command does not support search lists. To
  assign a logical name to a search list from within the en-
  vironment, use the system command to execute the DCL
  command ASSIGN with the /JOB qualifier. For example:
  $ ASSIGN/JOB DUA0:[MR.X],DUA0:[MR.Y] TWO$DIRECTORIES: