shell 的一些條件判斷

標籤：shell

  1. shell判斷檔案,目錄是否存在或者具有許可權
2. #!/bin/sh
3.
4. myPath="/var/log/httpd/"
5. myFile="/var /log/httpd/access.log"
6.
7. # 這裡的-x 參數判斷$myPath是否存在並且是否具有可執行許可權
8. if [ ! -x "$myPath"]; then
9. mkdir "$myPath"
10. fi
11.
12. # 這裡的-d 參數判斷$myPath是否存在
13. if [ ! -d "$myPath"]; then
14. mkdir "$myPath"
15. fi
16.
17. # 這裡的-f參數判斷$myFile是否存在
18. if [ ! -f "$myFile" ]; then
19. touch "$myFile"
20. fi
21.
22. # 其他參數還有-n,-n是判斷一個變數是否是否有值
23. if [ ! -n "$myVar" ]; then
24. echo "$myVar is empty"
25. exit 0
26. fi
27.
28. # 兩個變數判斷是否相等
29. if [ "$var1" = "$var2" ]; then
30. echo ‘$var1 eq $var2‘
31. else
32. echo ‘$var1 not eq $var2‘
33. fi

-f 和-e的區別
Conditional Logic on Files

-a file exists.
-b file exists and is a block special file.
-c file exists and is a character special file.
-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) bit set.
-G file exists and has the same group ID as this process.
-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 this process.
-p file exists and is a first in, first out (FIFO) special file or
named pipe.
-r file exists and is readable by the current process.
-s file exists and has a size greater than zero.
-S file exists and is a socket.
-t file descriptor number fildes is open and associated with a
terminal device.
-u file exists and has its setuid(2) bit set.
-w file exists and is writable by the current process.
-x file exists and is executable by the current process.
-z string length is zero.

是用 -s 還是用 -f 這個區別是很大的！

本文出自 “修仙的兔子” 部落格，請務必保留此出處http://tarstingo.blog.51cto.com/9408124/1586513

shell 的一些條件判斷