转http://blog.csdn.net/hittata/article/details/7042779

1. #/bin/bash  
3. printf "*************************************\n"  
4. echo " cat file whiel read line"  
5. cat test.txt |while read line  
6. do  
7.   echo $line;  
8. done  
10. printf "*************************************\n"  
11. echo "while read line <file"  
12. while read line  
13. do  
14.   echo $line;  
15. done <test.txt
17. printf "*************************************\n"  
18. echo "for line in cat test.txt"  
19. SAVEIFS=$IFS  
20. IFS=$(echo -en "\n")  
21. for line in $(cat test.txt)  
22. do  
23.   echo  $line;  
24. done  
25. IFS=$SAVEIFS 

注意：for line in $(cat test.txt)   当文件中有空格或者tab 时，一定要设置一下IFS变量。