Extract a PostgreSQL database cluster into a script file or other archive file. More information: https://www.postgresql.org/docs/current/app-pg-dumpall.html.
pg_dumpall > path/to/file.sql
pg_dumpall -U|--username username > path/to/file.sql
pg_dumpall -h host -p port > output_file.sql
pg_dumpall -a|--data-only > path/to/file.sql
pg_dumpall -s > output_file.sql