[size=large]管线符[/size]
[size=medium]借助Linux所提供的管线符“|”将两个命令隔开，管线符右边命令的输出都会作为管线符左边命令的输入。连续使用管线意味着第一个命令的输出会作为第二个命令的输入linux apache 虚拟主机，第二个命令的输出又会作为第三个命令的输入linux输出重定向命令linux输出重定向命令wps for linux，依这种推。下边来瞧瞧管线是怎样在构造一条Linux命令中得到应用的。[/size]


[developer@app02v /data/html/m.expai.com]$ ps -ax|grep api
Warning: bad syntax, perhaps a bogus '-'? See /usr/share/doc/procps-3.2.8/FAQ
13676 ? Sl 10:14 java -classpath /data/html/api.expai.com/lib/*:/data/html/api.expai.com/conf/ com.expai.server.APIServer
31779 pts/1 S+ 0:00 grep api

[size=large]重定向[/size]
[size=medium]>将stdout(标准输出)重定向到文件(覆盖)[/size]


[duming@app01v /data]$ ll > outfile
[duming@app01v /data]$ ll
؜ԃ 20
drwxrwxrwx 2 developer developer 4096 12Ղ 6 2013 backup
drwxrwxr-x 3 duming duming 4096 1Ղ 16 2014 htdocs
drwxrwxrwx 9 developer developer 4096 8Ղ 6 13:34 html
drwxrwxrwx 9 developer developer 4096 7Ղ 31 18:32 logs
-rw-rw-r-- 1 duming duming 300 8Ղ 10 23:20 outfile
[duming@app01v /data]$ cat outfile
؜ԃ 16
drwxrwxrwx 2 developer developer 4096 12Ղ 6 2013 backup
drwxrwxr-x 3 duming duming 4096 1Ղ 16 2014 htdocs
drwxrwxrwx 9 developer developer 4096 8Ղ 6 13:34 html
drwxrwxrwx 9 developer developer 4096 7Ղ 31 18:32 logs
-rw-rw-r-- 1 duming duming 0 8Ղ 10 23:20 outfile
[duming@app01v /data]$

[size=medium]>>将stdout(标准输出)重定向到文件(追加)[/size]



[duming@app01v /data/html]$ ll >> /data/outfile
[duming@app01v /data/html]$ cat /data/outfile
؜ԃ 16
drwxrwxrwx 2 developer developer 4096 12Ղ 6 2013 backup
drwxrwxr-x 3 duming duming 4096 1Ղ 16 2014 htdocs
drwxrwxrwx 9 developer developer 4096 8Ղ 6 13:34 html
drwxrwxrwx 9 developer developer 4096 7Ղ 31 18:32 logs
-rw-rw-r-- 1 duming duming 0 8Ղ 10 23:20 outfile
؜ԃ 28
drwxrwxrwx 6 developer developer 4096 7Ղ 23 16:44 api.expai.com
drwxrwxrwx 9 developer developer 4096 12Ղ 20 2013 m.expai.com
drwxrwxrwx 4 developer developer 4096 10Ղ 24 2013 mongo.expai.com
drwxrwxrwx 5 developer developer 4096 1Ղ 10 2014 r.expai.com
drwxrwxr-x 7 developer developer 4096 7Ղ 31 17:59 searchimg.expai.com
drwxrwxrwx 2 developer developer 4096 1Ղ 17 2014 shibin
drwxrwxrwx 5 developer developer 4096 12Ղ 4 2013 spider.expai.com
[duming@app01v /data/html]$

[size=medium]2>讲stderr(标准错误)重定向到文件(覆盖)[/size]


[duming@app01v /data/html]$ ll www.baidu.com
ls: Ϟ·¨·Ďɷww.baidu.com: ûԐҸþ»倂¼
[duming@app01v /data/html]$ ll www.baidu.com 2>/data/outfile
[duming@app01v /data/html]$ cat /data/outfile
ls: Ϟ·¨·Ďɷww.baidu.com: ûԐҸþ»倂¼
[duming@app01v /data/html]$

[size=medium]2>&1讲stderr(标准错误)和stdout(标准输出)结合[/size]
[size=medium]