linux 命令之 tee

名称：tee

位置：/usr/bin/tee

权限：所有用户

作用：双向重定向，会同时将数据流送与文件和屏幕；而输出到屏幕的，就是stdout，可以让下一下命令继续处理。

用法：tee [OPTION]... [FILE]...

选项：

-a, --append append to the given FILEs, do not overwrite

追加

双向重定向，在写入文件last.list之后，还能输出到屏幕上。

last |tee last.list
cwjy1202 pts/0        :0               Sat Jan 10 22:14   still logged in
reboot   system boot  3.2.0-24-generic Sat Jan 10 21:45 - 23:02  (01:16)
cwjy1202 pts/0        :0.0             Sat Jan 10 19:24 - down   (00:00)
reboot   system boot  3.2.0-24-generic Sat Jan 10 14:17 - 19:24  (05:07)
reboot   system boot  3.2.0-24-generic Fri Jan  9 20:50 - 22:50  (01:59)
cwjy1202 pts/0        :0               Thu Jan  8 22:08 - 23:16  (01:08)
reboot   system boot  3.2.0-24-generic Thu Jan  8 21:45 - 23:17  (01:31)
cwjy1202 pts/2        :0               Wed Jan  7 23:22 - 00:27  (01:05)
cwjy1202 pts/0        :0               Wed Jan  7 23:04 - 00:27  (01:23)
reboot   system boot  3.2.0-24-generic Wed Jan  7 23:03 - 00:27  (01:23)
cwjy1202 pts/2        :0               Tue Jan  6 23:10 - 23:46  (00:36)
cwjy1202 pts/0        :0               Tue Jan  6 22:32 - 23:46  (01:13)
reboot   system boot  3.2.0-24-generic Tue Jan  6 19:32 - 23:46  (04:13)
cwjy1202 pts/0        :0               Tue Jan  6 00:24 - 00:46  (00:21)
reboot   system boot  3.2.0-24-generic Mon Jan  5 20:59 - 00:46  (03:47)
cwjy1202 pts/0        :0               Sat Jan  3 20:33 - 00:39  (04:06)
cwjy1202 pts/0        :0               Sat Jan  3 19:23 - 19:24  (00:00)
reboot   system boot  3.2.0-24-generic Sat Jan  3 19:12 - 00:41  (05:28)
cwjy1202 pts/2        :0               Sat Jan  3 14:58 - 17:04  (02:05)
cwjy1202 pts/1        :0               Sat Jan  3 14:57 - 17:04  (02:07)
reboot   system boot  3.2.0-24-generic Sat Jan  3 14:54 - 17:05  (02:10)

wtmp begins Fri Jan  2 17:17:32 2015

注意：上名的tee命令并没有加选项 -a，这样默认文件将会被覆盖。

下面的例子，last的信息在写入文件last.list，同时还能被sed 命令处理

$ last |tee  -a last.list| sed -n '1p'
cwjy1202 pts/0        :0               Sat Jan 10 22:14   still logged in