shell获取用户名和uid

# echo "$USER"
user

# echo `id -u`
503

# echo `whoami`
user

# echo `who am i`
user pts/1 2009-10-26 10:49 (:0.0)

# who
user     tty1         2009-10-26 09:29 (:0)
user     pts/0        2009-10-26 10:43 (:0.0)
user     pts/1        2009-10-26 10:49 (:0.0)

# echo "$UID"
503

注：都在env中

用户和权限
http://blog.csdn.net/zhangxuechao_/article/details/46440335