Another way: ignore errors.
if ! getent passwd firebird >/dev/null; then adduser --system --quiet --home /var/lib/firebird \ --group --gecos "Firebird Database Administator" firebird fi
Another way: ignore errors.
if ! getent passwd firebird >/dev/null; then
- -group --gecos "Firebird Database Administator" firebird
adduser --system --quiet --home /var/lib/firebird \
fi