我写了个脚本，可是现在自己看不懂了

sipingal

麻烦那位Shell高手帮帮忙解释一下

1. 
   
2. #!/bin/sh
   
3. # echotwolines.sh
   
4. tmpfile="/tmp/.echotwolines.tmp-`date  +%H-%M-%S--%y`"
   
5. touch $tmpfile
   
6. exec 8<&0
   
7. exec 8<$tmpfile
   
8. read line1
   
9. read line2
   
10. read line3
    
11. exec 0<&8
    
12. rm -rf $tmpfile
    
13. echo $line1
    
14. echo $line2
    

复制代码

sunmoon1997

  Moving File Descriptors
       The redirection operator

              [n]<&digit-

       moves the file descriptor digit to file descriptor n, or  the  standard
       input (file descriptor 0) if n is not specified.  digit is closed after
       being duplicated to n.

       Similarly, the redirection operator

              [n]>&digit-

       moves the file descriptor digit to file descriptor n, or  the  standard
       output (file descriptor 1) if n is not specified.