a) u want grant select prinileges for all users.
b) u want grant select prinileges for 1 user only.
in both cases u should create some script, for a) to user PUBLIC and for b) to USER_NAME (for example for SCOTT).
set pagesize 0;
set linesize 120;
...
spool grt_view.sql;
a) select 'grant select on '||object_name||' to PUBLIC;' from all objects where object_type='VIEW' and object_name like 'V&%' or object_name like 'DBA\_%';
b) select 'grant select on '||object_name||' to SCOTT;' from all objects where object_type='VIEW' and object_name like 'V&%' or object_name like 'DBA\_%';