shell 判断文件、目录是否存在

hell判断文件是否存在

  1.shell判断文件,目录是否存在或者具有权限 

2. #!/bin/sh 

3. 

4. myPath="/var/log/httpd/" 

5. myFile="/var /log/httpd/access.log" 

6. 

7. # 这里的-x 参数判断$myPath是否存在并且是否具有可执行权限 

8. if [ ! -x "$myPath"]; then 

9. mkdir "$myPath" 

10. fi 

11. 

12. # 这里的-d 参数判断$myPath是否存在 

13. if [ ! -d "$myPath"]; then 

14. mkdir "$myPath" 

15. fi 

16. 

17. # 这里的-f参数判断$myFile是否存在 

18. if [ ! -f "$myFile" ]; then 

19. touch "$myFile" 

20. fi 

21. 

22. # 其他参数还有-n,-n是判断一个变量是否是否有值 

23. if [ ! -n "$myVar" ]; then 

24. echo "$myVar is empty" 

25. exit 0 

26. fi 

27. 

28. # 两个变量判断是否相等 

29. if [ "$var1" = "$var2" ]; then 

30. echo '$var1 eq $var2' 

31. else 

32. echo '$var1 not eq $var2' 

33. fi 

-f 和-e的区别 

Conditional Logic on Files 

-a file exists. 

-b file exists and is a block special file. 

-c file exists and is a character specialfile. 

-d file exists and is a directory. 

-e file exists (just the same as -a). 

-f file exists and is a regular file. 

-g file exists and has its setgid(2) bitset. 

-G file exists and has the same group ID as thisprocess. 

-k file exists and has its sticky bit set. 

-L file exists and is a symbolic link. 

-n string length is not zero. 

-o Named option is set on. 

-O file exists and is owned by the user ID of thisprocess. 

-p file exists and is a first in, first out (FIFO) special fileor 

named pipe. 

-r file exists and is readable by the currentprocess. 

-s file exists and has a size greater thanzero. 

-S file exists and is a socket. 

-t file descriptor number fildes is open and associated witha 

terminal device. 

-u file exists and has its setuid(2) bitset. 

-w file exists and is writable by the currentprocess. 

-x file exists and is executable by the currentprocess. 

-z string length is zero. 

是用 -s 还是用 -f 这个区别是很大的！