Bash Shell编程

botang

1. #!/bin/sh
   
2. read -p "Please input number1: " V_NUM1
   
3. read -p "Please input number2: " V_NUM2
   
4. bc <<EOF
   
5. scale=10
   
6. $V_NUM1/$V_NUM2
   
7. quit
   
8. EOF
   

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1. 
   
2. SUB_BC() {
   
3. read -p "Please input number1: " V_NUM1
   
4. read -p "Please input number2: " V_NUM2
   
5. bc <<-EOF
   
6.   scale=10
   
7.   $V_NUM1/$V_NUM2
   
8.   quit
   
9. EOF
   
10. }
    
11. 
    

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1. 
   
2. #!/bin/sh
   
3. . ./2.func
   
4. 
   
5. SUB_BC
   

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了解变量，和存储位置参数的变量：

1. SUB_A() {
   
2.   echo $1 $2 $3 $4 $5 $6 $7 $8 $9 $10
   
3.   echo $*
   
4.   echo $#
   
5.   echo $?
   
6. }
   

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1. 
   
2. #!/bin/sh
   
3. 
   
4. . ./5.func
   
5. 
   
6. SUB_A 1 2 3 4 5 6 7 8 9 a
   

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[root@server3 labs]# ./5.sh
1 2 3 4 5 6 7 8 9 10
1 2 3 4 5 6 7 8 9 a
10
0

1. SUB_A() {
   
2.   echo $1 $2 $3 $4 $5 $6 $7 $8 $9 ${10}
   
3.   echo $*
   
4.   echo $#
   
5.   echo $?
   
6. }

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[root@server3 labs]# ./5.sh
1 2 3 4 5 6 7 8 9 a
1 2 3 4 5 6 7 8 9 a
10
0
------------------------------------------------------

$() 会自动把输出中的回车，自动替换成空格：








[root@server3 labs]# seq 100  -2 0
100
98
96
94
92
90
88
86
84
82
80
78
76
74
72
70
68
66
64
62
60
58
56
54
52
50
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
[root@server3 labs]# A=$(seq 100  -2 0)
[root@server3 labs]# echo $A
100 98 96 94 92 90 88 86 84 82 80 78 76 74 72 70 68 66 64 62 60 58 56 54 52 50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0
[root@server3 labs]#

1. [root@server3 labs]# echo $[ $RANDOM % 60 +1 ]
   
2. 36
   
3. [root@server3 labs]# echo $[ $RANDOM % 60 +1 ]
   
4. 14
   
5. [root@server3 labs]# echo $[ $RANDOM % 60 +1 ]
   
6. 58
   
7. [root@server3 labs]# echo $[ $RANDOM % 60 +1 ]
   
8. 27
   
9. [root@server3 labs]# echo $[ $RANDOM % 60 +1 ]
   
10. 46
    
11. [root@server3 labs]# echo $[ $RANDOM % 60 +1 ]
    
12. 18
    
13. [root@server3 labs]# echo $[ $RANDOM % 60 +1 ]
    
14. 6
    
15. [root@server3 labs]# echo $[ $RANDOM % 60 +1 ]
    
16. 21
    

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1. [root@server3 /]# for i in * ; do du -s  $i  ; done |sort -n
   
2. du: cannot access ‘proc/68253/task/68253/fd/3’: No such file or directory
   
3. du: cannot access ‘proc/68253/task/68253/fdinfo/3’: No such file or directory
   
4. du: cannot access ‘proc/68253/fd/4’: No such file or directory
   
5. du: cannot access ‘proc/68253/fdinfo/4’: No such file or directory
   
6. 0       bin
   
7. 0       dev
   
8. 0       lib
   
9. 0       lib64
   
10. 0       media
    
11. 0       nfsserver
    
12. 0       opt
    
13. 0       proc
    
14. 0       sbin
    
15. 0       srv
    
16. 0       sys
    
17. 4       mnt
    
18. 20      home
    
19. 564     tmp
    
20. 2356    lost+found
    
21. 11128   run
    
22. 48624   etc
    
23. 107620  root
    
24. 148236  boot
    
25. 1113676 var
    
26. 3683376 usr
    
27. [root@server3 /]#
    

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-------------------------------------------------------------------------
事件观察者：

1. #!/bin/sh
   
2. 
   
3. echo "Waiting for the file: "
   
4. until [ -f ./6.txt  ]
   
5. do
   
6. sleep 1
   
7. done
   
8. 
   
9. echo "The file exists."
   

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1. 
   
2. #!/bin/sh
   
3. 
   
4. echo "Waiting for the file: "
   
5. while [ ! -f ./7.txt  ]
   
6. do
   
7. sleep 1
   
8. done
   
9. 
   
10. echo "The file exists."
    
11. 
    

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1.sh ：

1. 
   
2. #!/bin/sh
   
3. 
   
4. read -p "Please input color: " V_C
   
5. 
   
6. case "$V_C" in
   
7. r)
   
8. echo "redhat"
   
9. ;;
   
10. g)
    
11. echo "green"
    
12. ;;
    
13. *)
    
14. echo "other color"
    
15. ;;
    
16. esac
    
17. 
    

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2.sh

1. #!/bin/sh
   
2. 
   
3. if [ $# -eq 0 ]
   
4. then
   
5. echo "No argument"
   
6. exit 1
   
7. fi
   
8. 
   
9. if [ ! -f $1 ]
   
10. then
    
11. echo "No file"
    
12. exit 2
    
13. fi
    
14. 
    
15. V_F=$(cat $1)
    
16. 
    
17. for i in $V_F
    
18. do
    
19. echo "useradd -s /sbin/nologin $i"
    
20. done
    
21. 
    

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