pg_dumpall:tldr:faa60

This command is used to perform a database backup using the "pg_dumpall" utility in PostgreSQL. It takes a snapshot of the entire database cluster, including all databases, roles, tablespaces, and other necessary metadata.

Here is an explanation of the command parts:

1. "pg_dumpall" - This is the utility provided by PostgreSQL that performs the actual backup process. It is used to generate a plain-text SQL script containing all the necessary commands to recreate the entire database cluster.

2. ">" - This is a redirection operator in the shell that redirects the output of the command to a file instead of displaying it on the console.

3. "${filename-sql}" - This is a variable that represents the desired filename for the backup file. The "-sql" part is a placeholder for the file extension, which can be ".sql" or any other desired extension.

Overall, the command runs the "pg_dumpall" utility and redirects its output to a file with the chosen filename. The resulting file will contain the SQL script necessary to restore the entire PostgreSQL database cluster.