When using PostgreSQL DBMS, you may need to run some SQL commands to populate a database or run specific commands. You may also want to run these commands as a specific user. If that user doesn’t use peer authentication, you’ll have to run the SQL file in the psql shell. To learn how to do this, follow the steps below.
Step 1: Locate the SQL file
Locate the SQL file you want to run and copy its location. See the following example.
```bash
/home/me/projects/run-sql-tut/list-databases.sql
```
`me` is the current user's username. Replace it with your username.
Step 2: Log into the `psql` shell
```bash
sudo -iu postgres psql
```
##
Step 3: Execute the SQL file
```bash
\i /home/me/projects/run-sql-tut/list-databases.sql
```
This should give an output similar to:
```
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-------------+----------+----------+---------+---------+-----------------------
postgres | postgres | UTF8 | C.UTF-8 | C.UTF-8 |
template0 | postgres | UTF8 | C.UTF-8 | C.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | C.UTF-8 | C.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
(3 rows)
```