在postgres用户下输入以下指令：

例如创建名为ru的用户：
createuser -r -d -s ru

createuser [options] 用户名
【可以通过createuser –help命令得到帮助信息】
（
   Usage:
 createuser [OPTION]… [ROLENAME]

Options:
 -c, –connection-limit=N  connection limit for role (default: no limit)
 -d, –createdb            role can create new databases
 -D, –no-createdb         role cannot create databases
 -e, –echo                show the commands being sent to the server
 -E, –encrypted           encrypt stored password
 -i, –inherit             role inherits privileges of roles it is a
                           member of (default)
 -I, –no-inherit          role does not inherit privileges
 -l, –login               role can login (default)
 -L, –no-login            role cannot login
 -N, –unencrypted         do not encrypt stored password
 -P, –pwprompt            assign a password to new role
 -r, –createrole          role can create new roles
 -R, –no-createrole       role cannot create roles
 -s, –superuser           role will be superuser
 -S, –no-superuser        role will not be superuser
 –help                    show this help, then exit
 –version                 output version information, then exit

Connection options:
 -h, –host=HOSTNAME       database server host or socket directory
 -p, –port=PORT           database server port
 -U, –username=USERNAME   user name to connect as (not the one to create)
 -w, –no-password         never prompt for password
 -W, –password            force password prompt

If one of -d, -D, -r, -R, -s, -S, and ROLENAME is not specified, you will
be prompted interactively.

）

5.创建数据库
  例如创建名为mydb的数据库
   createdb  mydb
  createdb [options] 数据库名
 
Usage:
 createdb [OPTION]… [DBNAME] [DESCRIPTION]

Options:
 -D, –tablespace=TABLESPACE  default tablespace for the database
 -e, –echo                   show the commands being sent to the server
 -E, –encoding=ENCODING      encoding for the database
 -l, –locale=LOCALE          locale settings for the database
     –lc-collate=LOCALE      LC_COLLATE setting for the database
     –lc-ctype=LOCALE        LC_CTYPE setting for the database
 -O, –owner=OWNER            database user to own the new database
 -T, –template=TEMPLATE      template database to copy
 –help                       show this help, then exit
 –version                    output version information, then exit

Connection options:
 -h, –host=HOSTNAME          database server host or socket directory
 -p, –port=PORT              database server port
 -U, –username=USERNAME      user name to connect as
 -w, –no-password            never prompt for password
 -W, –password               force password prompt

By default, a database with the same name as the current user is created.
6.删除数据库
  删除mydb数据库：
  dropdb mydb
 
  Usage:
 dropdb [OPTION]… DBNAME

Options:
 -e, –echo                show the commands being sent to the server
 -i, –interactive         prompt before deleting anything
 –help                    show this help, then exit
 –version                 output version information, then exit

Connection options:
 -h, –host=HOSTNAME       database server host or socket directory
 -p, –port=PORT           database server port
 -U, –username=USERNAME   user name to connect as
 -w, –no-password         never prompt for password
 -W, –password            force password prompt

7.连接数据库
例如我的数据库是123
psql  123
Usage:
 psql [OPTION]… [DBNAME [USERNAME]]

General options:
 -c, –command=COMMAND    run only single command (SQL or internal) and exit
 -d, –dbname=DBNAME      database name to connect to (default: “postgres”)
 -f, –file=FILENAME      execute commands from file, then exit
 -l, –list               list available databases, then exit
 -v, –set=, –variable=NAME=VALUE
                          set psql variable NAME to VALUE
 -X, –no-psqlrc          do not read startup file (~/.psqlrc)
 -1 (“one”), –single-transaction
                          execute command file as a single transaction
 –help                   show this help, then exit
 –version                output version information, then exit

Input and output options:
 -a, –echo-all           echo all input from script
 -e, –echo-queries       echo commands sent to server
 -E, –echo-hidden        display queries that internal commands generate
 -L, –log-file=FILENAME  send session log to file
 -n, –no-readline        disable enhanced command line editing (readline)
 -o, –output=FILENAME    send query results to file (or |pipe)
 -q, –quiet              run quietly (no messages, only query output)
 -s, –single-step        single-step mode (confirm each query)
 -S, –single-line        single-line mode (end of line terminates SQL command)

Output format options:
 -A, –no-align           unaligned table output mode
 -F, –field-separator=STRING
                          set field separator (default: “|”)
 -H, –html               HTML table output mode
 -P, –pset=VAR[=ARG]     set printing option VAR to ARG (see \pset command)
 -R, –record-separator=STRING
                          set record separator (default: newline)
 -t, –tuples-only        print rows only
 -T, –table-attr=TEXT    set HTML table tag attributes (e.g., width, border)
 -x, –expanded           turn on expanded table output

Connection options:
 -h, –host=HOSTNAME      database server host or socket directory (default: “local socket”)
 -p, –port=PORT          database server port (default: “5432″)
 -U, –username=USERNAME  database user name (default: “postgres”)
 -w, –no-password        never prompt for password
 -W, –password           force password prompt (should happen automatically)

For more information, type “\?” (for internal commands) or “\help” (for SQL
commands) from within psql, or consult the psql section in the PostgreSQL
documentation.

mydb=# 注：最后一行 mydb=#，这个提示符意味着您是数据库超级用户

二.Postgresql图形化管理工具pgAdmin3
  
以fedora为例
 yum install pgadmin3
 完成安装后在   应用程序->编程->pgAdmin3