文件描述符-File Describtor
stdin 0
stdout 1
stderr 2
重定向标准输出-redirect stdout >
[keysystem@localhost redirect]$ echo hello>file1 [keysystem@localhost redirect]$ echo world>file2 [keysystem@localhost redirect]$ cat file1 hello [keysystem@localhost redirect]$ cat file2 world [keysystem@localhost redirect]$ cat file1 >file [keysystem@localhost redirect]$ cat file hello [keysystem@localhost redirect]$ cat file2 >file [keysystem@localhost redirect]$ cat file world [keysystem@localhost redirect]$ cat file file file1 file2 [keysystem@localhost redirect]$ cat file1 >>file [keysystem@localhost redirect]$ cat file world hello [keysystem@localhost redirect]$ cat file1 file2 >file [keysystem@localhost redirect]$ cat file hello world [keysystem@localhost redirect]$
重定向错误输出-redirect stdout 2>
[keysystem@localhost redirect]$ ls shit ls: cannot access shit: No such file or directory [keysystem@localhost redirect]$ [keysystem@localhost redirect]$ ls shit >out.put ls: cannot access shit: No such file or directory [keysystem@localhost redirect]$ [keysystem@localhost redirect]$ cat out.put [keysystem@localhost redirect]$ ls shit 2>out.put [keysystem@localhost redirect]$ [keysystem@localhost redirect]$ cat out.put ls: cannot access shit: No such file or directory [keysystem@localhost redirect]$
重定向标准输入-redirect stdin <
[keysystem@localhost redirect]$ cat file hello world [keysystem@localhost redirect]$ [keysystem@localhost redirect]$ grep world <file world [keysystem@localhost redirect]$
管道命令-pipeline |
[keysystem@localhost redirect]$ cat files.txt d.txt a.txt f.html b.txt b.txt [keysystem@localhost redirect]$ cat files.txt |uniq d.txt a.txt f.html b.txt [keysystem@localhost redirect]$ cat files.txt |uniq|grep txt d.txt a.txt b.txt [keysystem@localhost redirect]$ cat files.txt |uniq|grep txt|sort a.txt b.txt d.txt [keysystem@localhost redirect]$