如果你像我一样运行macOS，你可能没有postgres用户。

当试图运行sudo -u postgres psql时，我得到了错误sudo: unknown user: postgres

幸运的是，postgres提供了可执行文件。

createuser -D /var/postgres/var-10-local --superuser --username=nick
createdb --owner=nick

然后我就可以毫无问题地访问psql了。

psql
psql (10.2)
Type "help" for help.

nick=#

如果您要从头创建一个新的postgres实例，下面是我所采取的步骤。我使用了一个非默认端口，因此可以运行两个实例。

mkdir /var/postgres/var-10-local
pg_ctl init -D /var/postgres/var-10-local

然后我用我喜欢的端口5433编辑/var/ postgresql.conf。

/Applications/Postgres.app/Contents/Versions/10/bin/postgres -D /Users/nick/Library/Application\ Support/Postgres/var-10-local -p 5433

createuser -D /var/postgres/var-10-local --superuser --username=nick --port=5433
createdb --owner=nick --port=5433

完成了!

其他的答案都不能让我完全满意。以下是Xubuntu 12.04.1 LTS上postgresql-9.1的工作原理。

Connect to the default database with user postgres: sudo -u postgres psql template1 Set the password for user postgres, then exit psql (Ctrl-D): ALTER USER postgres with encrypted password 'xxxxxxx'; Edit the pg_hba.conf file: sudo vim /etc/postgresql/9.1/main/pg_hba.conf and change "peer" to "md5" on the line concerning postgres: local      all     postgres     peer md5 To know what version of postgresql you are running, look for the version folder under /etc/postgresql. Also, you can use Nano or other editor instead of VIM. Restart the database : sudo /etc/init.d/postgresql restart (Here you can check if it worked with psql -U postgres). Create a user having the same name as you (to find it, you can type whoami): sudo createuser -U postgres -d -e -E -l -P -r -s <my_name> The options tell postgresql to create a user that can login, create databases, create new roles, is a superuser, and will have an encrypted password. The really important ones are -P -E, so that you're asked to type the password that will be encrypted, and -d so that you can do a createdb. Beware of passwords: it will first ask you twice the new password (for the new user), repeated, and then once the postgres password (the one specified on step 2). Again, edit the pg_hba.conf file (see step 3 above), and change "peer" to "md5" on the line concerning "all" other users: local      all     all     peer md5 Restart (like in step 4), and check that you can login without -U postgres: psql template1 Note that if you do a mere psql, it will fail since it will try to connect you to a default database having the same name as you (i.e. whoami). template1 is the admin database that is here from the start. Now createdb <dbname> should work.

Note: textdb is the database which you are going to explore with 'alex' user 

root@kalilinux:~# sudo su - postgres 
postgres=#  psql   
postgres=#  create database testdb;
postgres=#  create user alex with password 'alex';
postgres=# GRANT ALL PRIVILEGES ON DATABASE testdb TO alex;`enter code here`

有两种方法可以使用。两者都需要创建用户和数据库。

Using createuser and createdb, $ sudo -u postgres createuser --superuser $USER $ createdb mydatabase $ psql -d mydatabase Using the SQL administration commands, and connecting with a password over TCP $ sudo -u postgres psql postgres And, then in the psql shell CREATE ROLE myuser LOGIN PASSWORD 'mypass'; CREATE DATABASE mydatabase WITH OWNER = myuser; Then you can login, $ psql -h localhost -d mydatabase -U myuser -p <port> If you don't know the port, you can always get it by running the following, as the postgres user, SHOW port; Or, $ grep "port =" /etc/postgresql/*/main/postgresql.conf

旁注:postgres用户

我建议不要修改postgres用户。

It's normally locked from the OS. No one is supposed to "log in" to the operating system as postgres. You're supposed to have root to get to authenticate as postgres. It's normally not password protected and delegates to the host operating system. This is a good thing. This normally means in order to log in as postgres which is the PostgreSQL equivalent of SQL Server's SA, you have to have write-access to the underlying data files. And, that means that you could normally wreck havoc anyway. By keeping this disabled, you remove the risk of a brute force attack through a named super-user. Concealing and obscuring the name of the superuser has advantages.

只要浏览到你的安装目录，并执行这个文件“pg_env.bat”，所以在bin文件夹和执行pgAdmin.exe。毫无疑问，这一定有用!

这是我的解决方案:

su root
su postgres
psql