STORE is not available in iSQL*Plus.
STORE SET file_name[.ext] [ CRE[ATE | REP[LACE] | APP[END]]
See SAVE for information on the other terms and clauses in the STORE command syntax.
To store the current SQL*Plus system variables in a file named DEFAULTENV with the default command-file extension, enter
STORE SET DEFAULTENV
To append the current SQL*Plus system variables to an existing file called DEFAULTENV with the extension OLD, enter
STORE SET DEFAULTENV.OLD APPEND