使用&&和||进行混合状态的test

################################Start
Script#######################################
1 #!/bin/bash
2
3 a=24
4 b=47
5
6 if [ "$a" -eq 24 ] && [ "$b" -eq 47 ]
7 then
8 echo "Test #1 succeeds."
9 else
10 echo "Test #1 fails."
11 fi
12
13 # 错误: if [ "$a" -eq 24 && "$b" -eq 47 ]
14 #+ 尝试执行' [ "$a" -eq 24 '
15 #+ 因为没找到']'所以失败了.

16 #
17 # 注意: 如果 [[ $a -eq 24 && $b -eq 24 ]] 能够工作.
18 # 那这个[[]]的test 结构就比[]结构更灵活了.
19 #
20 # (在17 行的"&&"与第6 行的"&&"意义不同)
21 # Thanks, Stephane Chazelas, for pointing this out.
22
23
24 if [ "$a" -eq 98 ] || [ "$b" -eq 47 ]
25 then
26 echo "Test #2 succeeds."
27 else
28 echo "Test #2 fails."
29 fi
30
31
32 # -a 和-o 选项提供了
33 #+ 一种可选的混合test 方法.
34 # Thanks to Patrick Callahan for pointing this out.

35
36
37 if [ "$a" -eq 24 -a "$b" -eq 47 ]
38 then
39 echo "Test #3 succeeds."
40 else
41 echo "Test #3 fails."
42 fi
43
44
45 if [ "$a" -eq 98 -o "$b" -eq 47 ]
46 then
47 echo "Test #4 succeeds."
48 else
49 echo "Test #4 fails."
50 fi

51
52
53 a=rhino
54 b=crocodile
55 if [ "$a" = rhino ] && [ "$b" = crocodile ]
56 then
57 echo "Test #5 succeeds."
58 else
59 echo "Test #5 fails."

60 fi
61
62 exit 0
################################End
Script#########################################