decodedmrq · March 3, 2021 16:42 · Apr 25, 2020 · Apr 25, 2020 · Jan 29, 2017 · Jan 29, 2017
diff --git a/psql-error-fix.md b/psql-error-fix.md
@@ -46,10 +46,11 @@ You can, of course, also create more specific rules for a specific database or u
 
 5. Revert the changes in `pg_hba.conf` file from `trust` to `md5` and restart `postgresql`.
 
-<sup>* The file `pg_hba.conf` will most likely be at `/etc/postgresql/9.x/main/pg_hba.conf`
+##### pg_hba.conf file location
 
-To check location of pg_hba.conf connect to postgres db using psql then type SHOW hba_file; command.
+The file `pg_hba.conf` will most likely be at `/etc/postgresql/9.x/main/pg_hba.conf`
+To check location of pg_hba.conf connect to postgres db using psql then type `SHOW hba_file;` command.
 
-After change pg_hba.conf file, you can execute `SELECT pg_reload_conf();` or pg_ctl reload with superuser instead of restart postgresql service.</sup>
+After change pg_hba.conf file, you can execute `SELECT pg_reload_conf();` or pg_ctl reload with superuser instead of restart postgresql service.
 
 <sup>* [Source](http://stackoverflow.com/a/21889759/2945616) </sup>
diff --git a/psql-error-fix.md b/psql-error-fix.md
@@ -46,7 +46,10 @@ You can, of course, also create more specific rules for a specific database or u
 
 5. Revert the changes in `pg_hba.conf` file from `trust` to `md5` and restart `postgresql`.
 
+<sup>* The file `pg_hba.conf` will most likely be at `/etc/postgresql/9.x/main/pg_hba.conf`
 
-<sup>* The file `pg_hba.conf` will most likely be at `/etc/postgresql/9.x/main/pg_hba.conf`</sup>
+To check location of pg_hba.conf connect to postgres db using psql then type SHOW hba_file; command.
+
+After change pg_hba.conf file, you can execute `SELECT pg_reload_conf();` or pg_ctl reload with superuser instead of restart postgresql service.</sup>
 
 <sup>* [Source](http://stackoverflow.com/a/21889759/2945616) </sup>
diff --git a/psql-error-fix.md b/psql-error-fix.md
@@ -24,7 +24,9 @@ to
 
 You can, of course, also create more specific rules for a specific database or user, with some users having `peer` and others requiring passwords.
 
-#### After changing `pg_hba.conf` you'll need to restart PostgreSQL if it's running. E.g. `sudo service postgresql restart`
+> After changing `pg_hba.conf` you'll need to restart PostgreSQL if it's running. E.g. `sudo service postgresql restart`
+
+
 
 ##### Steps to change/create default `postgres` user's password:
 

diff --git a/psql-error-fix.md b/psql-error-fix.md
@@ -20,9 +20,30 @@ to
 
 - `md5` means it will always ask for a password, and validate it after hashing with `MD5`.
 
+- `trust` means it will never ask for a password, and always trust any connection.
+
 You can, of course, also create more specific rules for a specific database or user, with some users having `peer` and others requiring passwords.
 
-After changing `pg_hba.conf` you'll need to restart PostgreSQL if it's running. E.g. `sudo service postgresql restart`
+#### After changing `pg_hba.conf` you'll need to restart PostgreSQL if it's running. E.g. `sudo service postgresql restart`
+
+##### Steps to change/create default `postgres` user's password:
+
+1. `trust` connection by adding in `pg_hba.conf` file
+
+- `local all postgres trust`
+
+2. Restart postgresql service
+
+- `sudo service postgresql restart`
+
+3. `psql -U postgres`
+
+4. At the `postgres=#` prompt, change the user name `postgres` password:
+
+- `ALTER USER postgres with password ‘new-password’;`
+
+5. Revert the changes in `pg_hba.conf` file from `trust` to `md5` and restart `postgresql`.
+
 
 <sup>* The file `pg_hba.conf` will most likely be at `/etc/postgresql/9.x/main/pg_hba.conf`</sup>
 

diff --git a/psql-error-fix.md b/psql-error-fix.md
@@ -25,4 +25,5 @@ You can, of course, also create more specific rules for a specific database or u
 After changing `pg_hba.conf` you'll need to restart PostgreSQL if it's running. E.g. `sudo service postgresql restart`
 
 <sup>* The file `pg_hba.conf` will most likely be at `/etc/postgresql/9.x/main/pg_hba.conf`</sup>
+
 <sup>* [Source](http://stackoverflow.com/a/21889759/2945616) </sup>
diff --git a/psql-error-fix.md b/psql-error-fix.md
@@ -25,5 +25,4 @@ You can, of course, also create more specific rules for a specific database or u
 After changing `pg_hba.conf` you'll need to restart PostgreSQL if it's running. E.g. `sudo service postgresql restart`
 
 <sup>* The file `pg_hba.conf` will most likely be at `/etc/postgresql/9.x/main/pg_hba.conf`</sup>
-
 <sup>* [Source](http://stackoverflow.com/a/21889759/2945616) </sup>
diff --git a/psql-error-fix.md b/psql-error-fix.md
@@ -0,0 +1,29 @@
+## psql: FATAL: Peer authentication failed for user “postgres” (or any user)
+
+The connection failed because by default `psql` connects over UNIX sockets using `peer` authentication, that requires the current UNIX user to have the same user name as `psql`. So you will have to create the UNIX user `postgres` and then login as `postgres` or use `sudo -u postgres psql database-name` for accessing the database (and `psql` should **not** ask for a password).
+
+If you cannot or do not want to create the UNIX user, like if you just want to connect to your database for *ad hoc* queries, forcing a socket connection using `psql --host=localhost --dbname=database-name --username=postgres` (as pointed out by @meyerson answer) will solve your immediate problem.
+
+But if you intend to force password authentication over Unix sockets instead of the peer method, try changing the following `pg_hba.conf`* line:
+
+from
+
+    # TYPE DATABASE USER ADDRESS METHOD
+    local  all      all          peer
+
+to
+
+    # TYPE DATABASE USER ADDRESS METHOD
+    local  all      all          md5
+
+- `peer` means it will trust the identity (authenticity) of UNIX user. So not asking for a password.
+
+- `md5` means it will always ask for a password, and validate it after hashing with `MD5`.
+
+You can, of course, also create more specific rules for a specific database or user, with some users having `peer` and others requiring passwords.
+
+After changing `pg_hba.conf` you'll need to restart PostgreSQL if it's running. E.g. `sudo service postgresql restart`
+
+<sup>* The file `pg_hba.conf` will most likely be at `/etc/postgresql/9.x/main/pg_hba.conf`</sup>
+
+<sup>* [Source](http://stackoverflow.com/a/21889759/2945616) </sup>