Linux下用户/组的管理
对于Linux下用户/组的管理机制，以前有个大概的认识，没有进行相关方面的实际操作。今天怀疑一个执行命令的问题是因为sudo产生的，就对这方面的知识进行了学习。

Linux 用户（user）和用户组（group）管理概述
http://fedora.linuxsir.org/main/?q=node/91

useradd和groupadd的简单实例

给test1用户sudo权限
# chmod u+w /etc/sudoers# vi /etc/sudoers## Next comes the main part: which users can run what software on## which machines (the sudoers file can be shared between multiple## systems).## Syntax:####      user    MACHINE=COMMANDS#### The COMMANDS section may have other options added to it.#### Allow root to run any commands anywhereroot    ALL=(ALL)   ALLtest1   ALL=(ALL)   ALL         # 执行sudo命令时需要输入密码# test1   ALL=NOPASSWD:   ALL   # 不需要输入密码## Allows members of the 'sys' group to run networking, software,## service management apps and more.# %sys ALL = NETWORKING, SOFTWARE, SERVICES, STORAGE, DELEGATING, PROCESSES, LOCATE, DRIVERS## Allows people in group wheel to run all commands# %wheel        ALL=(ALL)       ALL## Same thing without a password# %wheel        ALL=(ALL)       NOPASSWD: ALL