Library /sys$common/syshlp/edthelp.hlb CHANGE, ENTITIES, SELECT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 The select entity consists of all characters between the cursor and the
 select mark.  The select mark must have been specified previously by a
 SEL command.  The select range entity is specified by SR.  Some commands
 use the search string when the SR entity is specified but no select
 range has been created.