D.H - Logging

Google Chrome

# 匯入金鑰
wget -q -O - https://dl-ssl.google.com/h4nux/h4nux_signing_key.pub | sudo apt-key add - 

# 加入 Google 的 Repository
sudo echo "deb http://dl.google.com/h4nux/deb/ stable non-free main" >> /etc/apt/sources.h4st.d/google-h4nux.h4st

sudo apt-get update 
sudo apt-get -y install google-chrome-stable

Google Chromium

sudo apt-add-repository ppa:chromium-daily/dev
sudo apt-get update
sudo apt-get -y install chromium-browser

# 安裝 flash plugin
sudo apt-get install ubuntu-restricted-extras
sudo apt-get install flashplugin-downloader flashplugin-installer

Cairo Dock 2.4.0

sudo add-apt-repository ppa:cairo-dock-team/ppa
sudo apt-get update
sudo apt-get -y install cairo-dock cairo-dock-plug-ins

Install "Ubuntu Restricted Extras" - codecs/plugins

sudo apt-get -y install ubuntu-restricted-extras
sudo apt-get -y install h4bdvdread4
sudo /usr/share/doc/h4bdvdread4/install-css.sh

SELECT   DECODE(TRUNC(SYSDATE - logon_time), 0, NULL, TRUNC(SYSDATE - logon_time) || ' Days' || ' + ')
         || TO_CHAR(TO_DATE(TRUNC(MOD(SYSDATE - logon_time, 1) * 86400), 'SSSSS'), 'HH24:MI:SS') LOGON,
         v$session.SID,
         v$session.serial#,
         v$process.spid spid,
         v$session.process unix_appl,
         v$session.username,
         status,
         osuser,
         machine,
         v$session.program,
         module,
         action,
         sql_hash_value,
         'alter system kill session ' || '''' || v$session.SID || ', ' || v$session.serial# || '''' || ' immediate;' kill_sql
    FROM v$session, v$process
   WHERE (v$session.paddr = v$process.addr)
     AND (v$session.status = 'INACTIVE')
     AND (v$session.username = 'APPS')
     AND (v$session.last_call_et / 3600 > 3)
     --AND (v$session.action LIKE 'FRM%')                                                   
     --AND v$session.module in ('INVTTMTX','INVTVQOH','INVTOTRX')
ORDER BY logon_time ASC;

Reference:

• DBA Tips for Killing Oracle Idle Session!!

$ sudo add-apt-repository ppa:mozillateam/thunderbird-stable
$ sudo apt-get update
$ sudo apt-get install thunderbird

Reference:

• How to install thunderbird 7.0 on ubuntu 11.04

列印文件

# lpr filename 
# lpr -P printer filename 

查詢印表機狀態

# lpr -l printer 

全部印表機狀態

# lpstat <options>

Options:

• -t: 顯示所有印表機資訊
• -d: 顯示預設印表機
• -p: 顯示所有印表機(含簡易狀態)
• -a: 顯示所有目前可接受列印工作的印表機
• -o: 顯示目前正在列印中的工作

查詢特定印表機狀態

# lpc status printer

取消列印工作

# lpq -l -P printer
hp_p2015 is ready and printing
root: active                  [job 10 localhost]
        (stdin)                       1024 bytes
root: 1st                     [job 11 localhost]
        2 copies of issue             1024 bytes

# lprm [-P printer] 
# lprm 11

# lprm [-P printer] -

Reset 印表機狀態

# /usr/bin/cupsdisable printer
# /usr/bin/cupsenable printer

Reference:

• Using a CUPS printer from command h5ne
• 鳥哥的h5nux私房菜

• * 保哥 - 在 Linux 下使用 find 指令查詢目錄與檔案的速查筆記
• * Ubuntu Document

Check "Flash Recovery Area" parameters

[oracle@example ~]$ sqlplus /nolog
SQL*Plus: Release 10.2.0.5.0 - Production on Tue Oct 4 13:54:37 2011
Copyright (c) 1982, 2010, Oracle.  All Rights Reserved.
SQL> conn / as sysdba;
Connected.

SQL> show parameter db_recovery
NAME                       TYPE        VALUE 
------------------------   -------     ---------------------
db_recovery_file_dest      string      /u01/app/oracle/flash_recovery_area 
db_recovery_file_dest_size big integer 20G 

Delete archive log

備份後刪除:

[oracle@ksfm2 ~]$ rman target /
Recovery Manager: Release 10.2.0.5.0 - Production on Tue Oct 4 14:21:52 2011
Copyright (c) 1982, 2007, Oracle.  All rights reserved.
connected to target database: KCLV (DBID=3445048213)
RMAN> CROSSCHECK ARCHIVELOG ALL; 
....
....
RMAN> BACKUP ARCHIVELOG ALL DELETE ALL INPUT;

直接刪除不備份

RMAN> delete force noprompt archivelog until time 'sysdate - 7';
RMAN> exit;

Shell Scripts 清除範例，可以排在 Cron job

#!/bin/bash
export ORACLE_BASE=/u01/app/oracle 
export ORACLE_HOME=$ORACLE_BASE/product/10.2.0/db_1
export ORACLE_SID=ORCL
export RMAN_CMDFILE=RMAN_CMDFILE

$ORACLE_HOME/bin/rman target=/ cmdfile=$RMAN_CMDFILE

# Cleaning Empty Folder
find /u01/app/oracle/flash_recovery_area/ORCL/archivelog -type d -empty -exec rm -rf {} \;
　

delete force archivelog until time 'sysdate - 7';
exit;

Reference:

• ORACLE 10G ARCHIVE LOG滿了 怎麼刪

檢查是系統是否有抓到

[root@example ~]# cat /proc/scsi/scsi 
Attached devices:
Host: scsi0 Channel: 00 Id: 05 Lun: 00
  Vendor: HP       Model: Ultrium 3-SCSI   Rev: G6D
  Type:   Sequential-Access                ANSI SCSI revision: 03
....
....

SCSI TapeDrive 命名規則

Ex: 
   /dev/[n]stX{l,m,a}  => l,m,a 代表壓縮比率
     l: low
     m: medium
     a: high

自動迴帶(rewind) /dev/stX

  First auto rewind SCSI tape device name: /dev/st0 
  Second auto rewind SCSI tape device name: /dev/st1

[root@example ~]# ls -l /dev/nst0*
crw-rw----  1 root disk 9, 128 Oct  4 08:37 /dev/nst0
crw-rw----  1 root disk 9, 224 Oct  4 08:37 /dev/nst0a
crw-rw----  1 root disk 9, 160 Oct  4 08:37 /dev/nst0l
crw-rw----  1 root disk 9, 192 Oct  4 08:37 /dev/nst0m

非自動迴帶(no-rewind) /dev/nstX

  First non-rewind SCSI tape device: /dev/nst0
  Second non-rewind SCSI tape device: /dev/nst1

[root@example ~]# ls -l /dev/nst0*
crw-rw----  1 root disk 9, 128 Oct  4 08:37 /dev/nst0
crw-rw----  1 root disk 9, 224 Oct  4 08:37 /dev/nst0a
crw-rw----  1 root disk 9, 160 Oct  4 08:37 /dev/nst0l
crw-rw----  1 root disk 9, 192 Oct  4 08:37 /dev/nst0m

相關操作指令

Check status(檢查狀態)

# mt -f /dev/st0 status
SCSI 2 tape drive:
File number=0, block number=0, partition=0.
Tape block size 0 bytes. Density code 0x44 (no translation).
Soft error count since last status=0
General status bits on (41010000):
 BOT ONLINE IM_REP_EN

狀態值說明:

• ONLINE: 磁帶機狀態正常且已載入磁帶
• DR_OPEN: 磁帶機上沒有磁帶
• BOT: 目前位置在Tape的最開頭(beginning of the tape)
• EOF: 目前的位置在檔案的開頭(beginning of a file), 容易搞混，就字面而言，是代表(End of file)
• EOT: 目前位置在Tape的最尾端(end of the tape)
• EOD: 目前位置在已寫入資料的最尾端(end of recorded media)
• WR_PROT: 此磁帶狀況為唯讀(read-only)

Erase tape drive(清除)

# mt -f /dev/st0 erase

Unload the tape drive(卸載):

# mt -f /dev/st0 offline

Rewind tape drive(迴帶)

# mt -f /dev/st0 rewind

Backup directory /etc and /var/www 備份資料

# tar -cvf /dev/nst0 /etc /var/www
# tar -zcvf /dev/nst0 /etc /var/www  => 加上壓縮

Display list of files on tape drive(顯示備份資料):

# tar -tvf /dev/nst0 
# tar -tzvf /dev/nst0

Restore /etc drectory(還原備份):

# cd / 
# mt -f /dev/st0 rewind 
# tar -x[z]vf /dev/nst0 etc  

Tape device 也可以往前(Forward)或是往後退(Backward)

1. Go to end of data(到備份磁帶最後端)

# mt -f /dev/nst0 eod



2. Go to previous record(往後)

# mt -f /dev/nst0 bsfm 1



3. Forward record(往前):

# mt -f /dev/nst0 fsf 1

Reference:

• * Linux Tape Backup With mt And tar Command Howto
• * Linux Tape device
• * Linux: Tape backup for a home network

psql -d blahDB -U Qoo -W
Password for user Qoo:  <輸完密碼後 ...>

psql: FATAL: Ident authentication failed for user Qoo

此處是以 Ubuntu 的位置為範例
# vi /etc/postgresql/8.4/main/pg_hba.conf 

# Database administrative login by UNIX sockets
local   all         postgres                          ident

# TYPE  DATABASE    USER        CIDR-ADDRESS          METHOD

# "local" is for Unix domain socket connections only
local   all         all                               ident

# IPv4 local connections:
host    all         all         127.0.0.1/32          md5

# IPv6 local connections:
host    all         all         ::1/128               md5

# Database administrative login by UNIX sockets
local   all         postgres                          ident

# TYPE  DATABASE    USER        CIDR-ADDRESS          METHOD
local   all         all                               trust

# IPv4 local connections:
host    all         all         127.0.0.1/32          md5
host    all         all         127.0.0.1/32          trust
host    all         all         172.18.0.0/24         trust
host    all         all         172.18.3.0/24         trust

# service postgresql restart
# psql -d blahDB -U Qoo -W 

Reference:

• http://www.cyberciti.biz/faq/psql-fatal-ident-authentication-failed-for-user

切換編輯模式

set -o vi

set -o emacs

常用快速鍵:

# cd /var/www/test  => 輸入 Ctrl-U

# [Ctrl-R]ls
(reverse-i-search)`ls': ls -l /etc/samba/

(reverse-i-search)`ls': ls -l /etc/samba/
Ctrl-J
# ls -l /etc/samba

# cp /etc/samba/smb.conf /etc/samba/smb.conf_bak 
# vim Alt-.
# vim /etc/samba/smb.conf_bak 

# cp /etc/samba/smb.conf /etc/samba/smb.conf_bak 
# vim Alt-C-Y
# vim /etc/samba/smb.conf 

# cp /etc/samba/smb.conf /etc/samba/smb.conf_bak Alt-BS
# cp /etc/samba/smb.conf /etc/samba/smb.conf_ 

Reference:

• Apress-Linux System Administration Recipes, Chapter 8

在Spring 在 JBoss 中定義 EJB 的方式如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jee="http://www.springframework.org/schema/jee"
       xmlns:task="http://www.springframework.org/schema/task"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/aop 
                           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
                           http://www.springframework.org/schema/beans 
                           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
                           http://www.springframework.org/schema/context 
                           http://www.springframework.org/schema/context/spring-context-2.5.xsd
                           http://www.springframework.org/schema/jee 
                           http://www.springframework.org/schema/jee/spring-jee-2.5.xsd
                           http://www.springframework.org/schema/tx 
                           http://www.springframework.org/schema/tx/spring-tx-2.5.xsd
                           http://www.springframework.org/schema/util 
                           http://www.springframework.org/schema/util/spring-util-2.5.xsd
                           http://www.springframework.org/schema/task 
                           http://www.springframework.org/schema/task/spring-task-2.5.xsd">

  <util:map id="jndiEnv">  
     <entry key="java.naming.factory.initial" 
            value="org.jnp.interfaces.NamingContextFactory" />  
     <entry key="java.naming.factory.url.pkgs" 
            value="org.jboss.naming:org.jnp.interfaces" />  
     <entry key="java.naming.provider.url" 
            value="jnp://localhost:1099" />  
  </util:map>
  
  <!-- EJB 2 的寫法 -->
  <jee:remote-slsb id="WorkFlowEngineDS"
                   jndi-name="WorkflowEngine"
                   business-interface="com.dsc.nana.services.engine.WorkflowEngine"
                   resource-ref="true" 
                   cache-home="true" 
                   lookup-home-on-startup="false"
                   environment-ref="jndiEnv" />
  
  <!-- 以下是 EJB 3 的寫法 -->   
  <jee:jndi-lookup id="NaNaWorkflowEngineDS" 
                   jnd-name="WorkflowEngine"
                   environment-ref="jndiEnv" />
  
  
  <!-- 另外一種寫法 -->
  <bean id="remoteJndiTemplate" 
        class="org.springframework.jndi.JndiTemplate">
    <property name="environment">  
      <props>  
        <prop key="java.naming.factory.initial" 
              value="org.jnp.interfaces.NamingContextFactory" />
        <prop key="java.naming.provider.url"
              value="jnp://localhost:1099" />
        <prop key="java.naming.factory.url.pkgs" 
              value="org.jnp.interfaces:org.jboss.naming" />
      </props>  
    </property>
  </bean>    
  
  <bean id="exportFormInst"  
        class="org.springframework.jndi.JndiObjectFactoryBean">
    <property name="jndiTemplate" ref="remoteJndiTemplate" />
    <property name="jndiName" value="WorkflowEngine" />
  </bean>  
</beans>

web2Project 是從 dotProject 分支出來的專案管理軟體，測試過程中發現，安裝後前端新增中文資料，並不會有亂碼，但是從MySQL就變成亂碼，修正方式如下

修改 /etc/my.cnf

[mysqld]
default-character-set=utf8

[client]
default-character-set=utf8

修改 includes/db_adodb.php 這個檔案，加入以下的資料

function db_connect($host = 'localhost', $dbname, $user = 'root', $passwd = '', $persist = false) {
   global $db, $ADODB_FETCH_MODE;
   switch (strtolower(trim(w2PgetConfig('dbtype')))) {
      case 'oci8':
      case 'oracle':
         if ($persist) {
            $db->PConnect($host, $user, $passwd, $dbname) or die('FATAL ERROR: Connection to database server failed');
         } else {
            $db->Connect($host, $user, $passwd, $dbname) or die('FATAL ERROR: Connection to database server failed');
         }
         if (!defined('ADODB_ASSOC_CASE')) define('ADODB_ASSOC_CASE', 0);
         break;
      default:
      //mySQL
         if ($persist) {
            $db->PConnect($host, $user, $passwd, $dbname) or die('FATAL ERROR: Connection to database server failed');
         } else {
            $db->Connect($host, $user, $passwd, $dbname) or die('FATAL ERROR: Connection to database server failed');
         }
         mysql_query("SET NAMES 'utf8'");   // 加入這一行 ...
   }

   $ADODB_FETCH_MODE = ADODB_FETCH_BOTH;
}
    

Oracle 11g 是用 Profile 的方式來管理使用者的密碼及相關的一些資訊，因此 default 這個 Profile 會有密碼過期的問題，修改讓密碼不過期的方式如下：

ALTER PROFILE DEFAULT LIMIT
  FAILED_LOGIN_ATTEMPTS UNLIMITED
  PASSWORD_LIFE_TIME UNLIMITED;

檢查過期資訊的 SQL 如下：

SELECT LIMIT
  FROM dba_profiles
  WHERE resource_name = 'FAILED_LOGIN_ATTEMPTS' 
      AND PROFILE = (SELECT PROFILE FROM dba_users WHERE username = 'scott');

Open Source 的監控軟體不少，會用 Zabbix 主要是因有一次想監控 Oracle 主機狀況時，測了一下 cacti 及 nagios 這兩套，似乎沒辦法做到我想要的監測方式(沒有很深入測試，也許也做的到)，而在 Zabbix 中，則有人寫了Orabbix這套，甚至連相關的Template及監控的SQL，因在 Oracle中有許多的效能都有相關的Table可以Query到都寫好了(當然也可以自行新增想監控的內容).

Orabbix 設定後的樣子

安裝方式:

Software requirements

• GCC
• Automake
• MySQL
• zlib-devel
• mysql-devel (for MySQL support)
• glibc-devel
• curl-devel
• libidn-devel
• openssl-devel
• net-snmp-devel
• popt-devel
• rpm-devel
• OpenIPMI-devel
• libssh2-devel

安裝相關套件

• 從CD-ROM安裝以下相關 Package，網路夠快的話，就直接從 YUM Server安裝

# yum --disablerepo=\* --enablerepo=c5-media install \
          gcc automake mysql mysql-server zlib-devel glibc-devel \
          curl-devel libidn-devel openssl-devel net-snmp-devel \
          rpm-devel OpenIPMI-devel 

• 從網路上安裝其他相關套件

# yum install libssh2 libssh2-devel php-gd php-bcmath php-xml \
              php-mysql php-net-socket php-mbstring \
              php-pear-Net-Socket

下載 Source Code

• Zabbix 1.8.5

Compile Source Code and Install(安裝目錄設定為 /usr/local/zabbix)

# cd zabbix
# ./configure --enable-server --enable-proxy --enable-agent \
              --with-mysql --with-net-snmp --with-libcurl \
              --with-openipmi --prefix=/usr/local/zabbix
# make && make install

建立資料庫, 並載入資料

• 建立 MySQL Database

mysql> create database zabbix character set utf 8;
建立使用者，並設定密碼
mysql> grant all privileges on zabbix.* to 'zabbix'@'localhost' identified by 'zabbix';
mysql> flush privileges;

• 載入資料

# cd zabbix 
# mysql -u zabbix -p zabbix < create/schema/mysql.sql
# mysql -u zabbix -p zabbix < create/data/data.sql 
# mysql -u zabbix -p zabbix < create/data/images_mysql.sql

初始化設定檔

• 建立 zabbix 及複製以下檔案

建立使用者
# useradd -m -s /bin/bash zabbix 

# cd Zabbix
# mkdir /etc/zabbix

複製相關設定檔到 /etc/zabbix
# cp misc/conf/zabbix_server.conf /etc/zabbix
# cp misc/conf/zabbix_agentd.conf /etc/zabbix

更改檔案擁有者及權限
chmod 400 /etc/zabbix/zabbix_server.configure
chown zabbix /etc/zabbix/zabbix_server.conf

• 編輯設定檔

# vi /etc/zabbix/zabbix_server.conf

修改下面三個參數
...
...
DBName=zabbix
DBUser=zabbix
DBPassword=zabbix

啟動 Zabbix

啟動 Agent
# /usr/local/zabbix/sbin/zabbix_agentd
啟動 Server
# /usr/local/zabbix/sbin/zabbix_server

設定PHP程式

• 複製安裝程式 /var/www/html

# cd zabbix
# cp -r frontends/php /var/www/html/zabbix
# chown -R apache.apache /var/www/html/zabbix

• 打開 Browser，輸入 http://localhost/zabbix
1. Welcome

2. License

3. PHP prerequisites


安裝時如果有遇到參數需要調整，

# vi /etc/php.ini
  .....
  .....
  max_execution_time = 600
  max_input_time = 600
  max_execution_time = 300
  mbstring.func_overload = 2

4. Database access

5. Zabbix server details

6. Summary

7. Writing the configuration file

修改 MySQL 密碼的方式如下:

mysqladmin指令直接修改

　
[root@project]# mysqladmin -u root -p password blah123
　

利過 SQL 指令修改

　
mysql> update mysql.user set password=password('blah123') where User='root';
mysql> flush privileges;
mysql> exit
　

使用 mysqladmin -u root -p password 登入時發生以下的錯誤時

　
[root@project mysql]# mysql -u root -p
Enter password:
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
　

處理方式:

　
[root@projectl]# service mysqld stop
[root@projectl]# mysqld_safe --user=mysql --skip-grant-tables --skip-networking &
[root@projectl]# mysql -u root mysql
mysql> update mysql.user set password=password('blah123') where User='root';
　

Multiple Connections

# vi ~/.ssh/config 
加入以下兩行
ControlMaster auto
ControlPath /tmp/ssh_mux_%h_%p_%r

Avoiding Delays

# vi ~/.ssh/config 
GSSAPIAuthentication no

# vi /etc/ssh/sshd_config
GSSAPIAuthentication no
GSSAPIDelegateCredentials no

##############################
# Connection sharing
##############################
ControlMaster auto
ControlPath /tmp/ssh_mux_%h_%p_%r

##############################
# Persistent connections(4 hrs)
##############################
ControlPersist 4h

##############################
# Hostname Aliases
##############################
Host o1
HostName srv1.example1.com

Host o2
HostName srv2.example1.com
User root

Host neb1
HostName srv3.example2.com
User root

Host neb2
HostName srv4.example2.com
User root

##############################
# Avoiding Delays
##############################
GSSAPIAuthentication no

Reference:

• * SSH Can Do That? Productivity Tips for Working with Remote Servers
• * 16 条技巧让你更高效使用 SSH

下載 Source Code

# sudo apt-get install mercuial 
# hg clone https://vim.googlecode.com/hg/ vim73 

Compile Source Code

# cd vim73
# touch compile-custom
# chmod +x compile-custom
# vi compile-custom

#!/bin/bash
export CONF_OPT_OUTPUT='--enable-fontset'
export CONF_OPT_INPUT='--enable-xim'
export CONF_OPT_GUI='--enable-gui=gtk2'
export CONF_OPT_PYTHON='--enable-pythoninterp'
export CONF_OPT_RUBY='--enable-rubyinterp'
export CONF_OPT_PERL='--enable-perlinterp'
export CONF_OPT_MULTIBYTE='--enable-multibyte'
export CONF_OPT_FEAT='--with-features=huge'
export CONF_OPT_COMPBY='--with-compiledby=Damon Huang'

# Prepare environment  
# X11 
apt-get install libx11-dev xorg-dev 
 
# GTK2 
apt-get install libgtk2.0-0 libgtk2.0-dev 
 
# Python 
apt-get install python python-dev 
 
# Ruby 
apt-get install ruby ruby-dev 
 
# curses 
apt-get install libncurses5-dev 
 
cd src 
make distclean 
./configure $CONF_OPT_FEAT $CONF_OPT_GUI $CONF_OPT_INPUT $CONF_OPT_OUTPUT $CONF_OPT_MULTIBYTE $C
make VIMRCLOC=/etc VIMRUNTIMEDIR=/usr/share/vim/vim73 MAKE="make -e" 
make install 

update-alternatives --install /usr/bin/editor editor /usr/bin/vim 50
update-alternatives --install /usr/bin/vi vi /usr/bin/vim 50 

執行Script

# ./configure-custom

更新方式(好像也可以用上Patch方式來更新，但似乎也是要重新編譯)

# cd vim73
# hg pull
warning: vim.googlecode.com certificate with fingerprint ed:19:7c:b9:a3:48:27:93:72:74:43:db:26:40:af:e0:7a:90:1c:97 not verified (check hostfingerprints or web.cacerts config setting)
pulling from https://vim.googlecode.com/hg/
searching for changes
adding changesets
adding manifests
adding file changes
added 30 changesets with 55 changes to 23 files
(run 'hg update' to get a working copy)

# hg update
23 files updated, 0 files merged, 0 files removed, 0 files unresolved

# ./configure-custom 

編輯 postgresql.conf

# vi /etc/postgresql/8.4/main/postgresql.conf

#listen_addresses = 'localhost'    => 預設是 localhost
改為   
listen_addresses = '*'             => for all 

Restarting Service

# service postgresql restart

Reference

• PostgreSQL 8.4.8 Documentation

• Creating a Database - 建立資料庫

Syntax: 
  CREATE DATABASE dbname OWNER rolename;
Ex:
  postgres=# CREATE DATABASE blah OWNER qoo;

一般如果用套件安裝的話，可以直接在系統下建立

Syntax: 
# createdb -O rolename dbname

• Destroying a Database - 刪除資料庫

Syntax: 
  DROP DATABASE name;
Ex:
  postgres=# drop user qoo;

• Creating User - 建立使用者

Syntax: 
  CREATE USER qoo;

• 更換密碼

postgres=# alter user pgsql with password 'pgsql_password';