ubuntu学习遇到的一些问题解决方案汇总

一、更新缺少公钥解决方法：

问题描述：NO_PUBKEY 16126D3A3E5C1192

sudo gpg --keyserver subkeys.pgp.net --recv 3E5C1192        ＃公钥后 8位
sudo gpg --export --armor 3E5C1192 | sudo apt-key add -

Ubuntu PPA 则为：
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com

二、Vsftpd错误：550 permission denied， #local_umask=022（默认077）；

530 permission denied， chmod -R 777 file

附chmod：chmod a+r file 所有用户增加file读权限

 chmod +rwx file 所有用户增加读写执行权限

 chmod u=rm,go=file 设置读写权限对file所有者，清空所有权限

 chmod -R u+r,go-r docs 对docs和其子目录所有文件增加读的权限，删除其他读

 chmod 4755 file 设置用户ID（SUID为4）

 chmod 6755 file 设置用户ID和组ID（SGID为2），sticky位代表1

SUID含义：文件的该位被设置为1，在该文件被执行时，该文件将以所有者的身份运行也就是说无论谁来执行这个文件，他都有文件所有者的特权，如果所有者是root的话，那么执行人就有超级用户的特权了，这是该位将变成一个安全漏洞，因此不要轻易设置该位。

三、删除一个文件夹所有文件：

  rm`find/path-typef`  

如果path目录下文件过多就会因为“参数列表过长”而报错无法执行。但改用xargs以后，问题即获解决。

  find/path-typef -print0 | xargs-0 rm  

本例中xargs将find产生的长串文件列表拆散成多个子串，然后对每个子串调用rm。这样要比如下使用find命令效率高的多。

  find/path-typef -execrm'{}'\;  

上面这条命令会对每个文件调用"rm"命令。当然使用新版的"find"也可以得到和"xargs"命令同样的效果：

  find/path-typef -execrm'{}'+  

xargs的作用一般等同于大多数Unix shell中的反引号，但更加灵活易用，并可以正确处理输入中有空格等特殊字符的情况。对于经常产生大量输出的命令如find、locate和grep来说非常有用。

四、使用secureCRT给linux发送文件：首先登陆linux系统，在Linux下安装lrzsz这个小工具，Ubuntu下可以使用命令：$sudo apt-get install lrzsz

五、关闭防火墙：

root@stgman-desktop:~# sudo ufw disable
防火墙在系统启动时自动禁用

六、安装wordpress提示数据库出错：

可能的问题：没有建数据库

以下创建WordPress需要的数据库和数据库用户

mysql> CREATE DATABASE db_wordpress;

七、修改软件源：

1、首先备份Ubuntu12.04源列表

sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup （备份下当前的源列表）

2、修改更新源

sudo gedit /etc/apt/sources.list （打开Ubuntu 12.04源列表文件）

3、把里面的列表替换成下面的列表

163源

deb http://mirrors.163.com/ubuntu/ precise main restricted
deb-src http://mirrors.163.com/ubuntu/ precise main restricted
deb http://mirrors.163.com/ubuntu/ precise-updates main restricted
deb-src http://mirrors.163.com/ubuntu/ precise-updates main restricted
deb http://mirrors.163.com/ubuntu/ precise universe
deb-src http://mirrors.163.com/ubuntu/ precise universe
deb http://mirrors.163.com/ubuntu/ precise-updates universe
deb-src http://mirrors.163.com/ubuntu/ precise-updates universe
deb http://mirrors.163.com/ubuntu/ precise multiverse
deb-src http://mirrors.163.com/ubuntu/ precise multiverse
deb http://mirrors.163.com/ubuntu/ precise-updates multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-updates multiverse
deb http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ precise-security main restricted
deb-src http://mirrors.163.com/ubuntu/ precise-security main restricted
deb http://mirrors.163.com/ubuntu/ precise-security universe
deb-src http://mirrors.163.com/ubuntu/ precise-security universe
deb http://mirrors.163.com/ubuntu/ precise-security multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-security multiverse
deb http://extras.ubuntu.com/ubuntu precise main
deb-src http://extras.ubuntu.com/ubuntu precise main

sohu源

deb http://mirrors.sohu.com/ubuntu/ precise main restricted
deb-src http://mirrors.sohu.com/ubuntu/ precise main restricted
deb http://mirrors.sohu.com/ubuntu/ precise-updates main restricted
deb-src http://mirrors.sohu.com/ubuntu/ precise-updates main restricted
deb http://mirrors.sohu.com/ubuntu/ precise universe
deb-src http://mirrors.sohu.com/ubuntu/ precise universe
deb http://mirrors.sohu.com/ubuntu/ precise-updates universe
deb-src http://mirrors.sohu.com/ubuntu/ precise-updates universe
deb http://mirrors.sohu.com/ubuntu/ precise multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precise multiverse
deb http://mirrors.sohu.com/ubuntu/ precise-updates multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precise-updates multiverse
deb http://mirrors.sohu.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precise-backports main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ precise-security main restricted
deb-src http://mirrors.sohu.com/ubuntu/ precise-security main restricted
deb http://mirrors.sohu.com/ubuntu/ precise-security universe
deb-src http://mirrors.sohu.com/ubuntu/ precise-security universe
deb http://mirrors.sohu.com/ubuntu/ precise-security multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precise-security multiverse
deb http://extras.ubuntu.com/ubuntu precise main
deb-src http://extras.ubuntu.com/ubuntu precise main

ubuntu.cn99.com源（推荐）:

deb http://ubuntu.cn99.com/ubuntu/ precise main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ precise-updates main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ precise-security main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ precise-backports main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu-cn/ precise main restricted universe multiverse

教育网源
如果你是在校大学生，可以使用校园网/教育网，就是用教育网的资源吧，尤其是支持ipv6的，那更新速度就按兆算了。

#电子科技大学

deb http://ubuntu.uestc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse

#中国科技大学

deb http://debian.ustc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-backports restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse

#北京理工大学

deb http://mirror.bjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe

4、更新源

sudo apt-get update