COPY _temp FROM PROGRAM 'curl -uri "https://url"';

_command := 'curl -uri "https://url?&page='||(10::text)||"';
COPY _temp FROM PROGRAM _command;`

ERROR:  syntax error at or near "_command"

COPY _temp FROM PROGRAM 'curl -uri "https://url?&page='||(10::text)||'"';

DO $$
DECLARE page integer;
BEGIN
FOR page IN SELECT i FROM generate_series(1, 10) AS t(i)
LOOP
    EXECUTE format($cmd$ COPY _temp
                         FROM PROGRAM 'curl -uri "https://url?&page=%s"$cmd$,
                   page::text);
END LOOP;
END; $$;

for i in $(seq 1 10); do
    psql -c "COPY _temp FROM PROGRAM 'curl -uri https://url?&page=${i}'"
done