demo1
简单的读取单个参数
#!/bin/bash
#ussing one command line parameter
factorial=1
for (( number = 1; number <= $1; number++ ))
do
factorial=$[ $factorial * $number ]
done
echo the factorial of $1 is $factorial
//
hadoop@master:~/shell_test/cin$ ./test1 3
the factorial of 3 is 6
hadoop@master:~/shell_test/cin$ ./test1 4
the factorial of 4 is 24
注意：
如果有多个参数，依次为$1 - $9,如果超过9个
如10，则为${10}
demo2
读取程序名字
#!/bin/bash
#testting $0 parameter
echo The command enter is: $0
#not include path
name=`basename $0`
echo the commadn name is $name
//result
hadoop@master:~/shell_test/cin$ ./test2
The command enter is: ./test2
the commadn name is test2
demo3
测试参数是否存在
#!/bin/bash
#testing parameter before use
if [ -n "$1" ]
then
echo Hello $1 gland to meet you
else
echo "sorry, you dont identify yourself."
fi
//result
hadoop@master:~/shell_test/cin$ ./test3
sorry, you dont identify yourself.
hadoop@master:~/shell_test/cin$ ./test3 a
Hello a gland to meet you
特殊参数变量
(1)$#
$# 统计命令行参数个数
if [ $# -ne 2 ]
then
fi
注意在字符串中直接输出需要，${!#}
(2) $* $@
$* 会将所有参数当成一个参数
$@ 变量会单独处理每个参数
demo4
shift移动变量
#!/bin/bash
# demonstrating the shift command
count=1
while [ -n "$1" ]
do
echo "Parameter #$count = $1"
count=$[ $count +1 ]
shift
done
//result
hadoop@master:~/shell_test/cin$ ./test4 kfd fjdslf
Parameter #1 = kfd
Parameter #2 = fjdslf
注意：
shift 2 移动两个参数
demo5
(1)处理简单选项
#!/bin/bash
#extracting command line options as parameters
while [ -n "$1" ]
do
case "$1" in
-a) echo "Fond the -a option" ;;
-b) echo "Fond the -b option" ;;
-c) echo "Found the -c option" ;;
*) echo "$1 is not an option" ;;
esac
shift
done
//
hadoop@master:~/shell_test/cin$ ./test5 -c
Found the -c option
hadoop@master:~/shell_test/cin$ ./test5 -b
Fond the -b option
hadoop@master:~/shell_test/cin$ ./test5 -d
-d is not an option
（2）分离参数和选项
#!/bin/bash
#extracting command line options as parameters
#-- as a seperate
while [ -n "$1" ]
do
case "$1" in
-a) echo "Fond the -a option" ;;
-b) echo "Fond the -b option" ;;
-c) echo "Found the -c option" ;;
--) shift
break ;;
*) echo "$1 is not an option" ;;
esac
shift
done
count=1
for parm in $@
do
echo "Parametrer #$count : $parm"
count=$[ $count + 1 ]
done
//
hadoop@master:~/shell_test/cin$ ./test6 -a -b -c -- fjd fdsjfld jflds
Fond the -a option
Fond the -b option
Found the -c option
Parametrer #1 : fjd
Parametrer #2 : fdsjfld
Parametrer #3 : jflds
hadoop@master:~/shell_test/cin$
(3)处理带值的选项
#!/bin/bash
#extracting command line options as parameters
#-- as a seperate
while [ -n "$1" ]
do
case "$1" in
-a) echo "Fond the -a option" ;;
-b) param=$2
echo "Found the -b option , with paramerter value $param"
shift ;;
-c) echo "Found the -c option" ;;
--) shift
break ;;
*) echo "$1 is not an option" ;;
esac
shift
done
count=1
for parm in $@
do
echo "Parametrer #$count : $parm"
count=$[ $count + 1 ]
done
//result
hadoop@master:~/shell_test/cin$ ./test7 -a -b nihao -c
Fond the -a option
Found the -b option , with paramerter value nihao
Found the -c option
hadoop@master:~/shell_test/cin$
demo6
获取用户输入
#!/bin/bash
#testing the read command
echo -n "Enter your name"
read name
echo "Heollo $name , welcome to my program"
//
hadoop@master:~/shell_test/cin$ ./test8
Enter your namechenhanghang
Heollo chenhanghang , welcome to my program
注意：
（1）-p 直接指定提示符号
read -p "input your name" name
（2）如果不指定变量名字，则会把变量放在 REPLY中
（3）-s 以隐藏方式读取
demo7
超时退出
#!/bin/bash
#timing the data entry
if read -t 5 -p "please input your name:" name
then
echo "Hello $name, welcome to my script"
else
echo
echo "Sorry, too slow"
fi
//
hadoop@master:~/shell_test/cin$ ./test9
please input your name:
Sorry, too slow
hadoop@master:~/shell_test/cin$
demo9
限定字符的个数
#!/bin/bash
#getting just one character of input
read -n1 -p "Do you want to continue [Y/N] " answer
case $answer in
Y | y) echo
echo "fine ,continue on..." ;;
N | n) echo
echo "OK googbye"
exit ;;
esac
echo "This is the end of the script"
//result
hadoop@master:~/shell_test/cin$ ./test10
Do you want to continue [Y/N] Y
fine ,continue on...
This is the end of the script
hadoop@master:~/shell_test/cin$
hadoop@master:~/shell_test/cin$ ./test10
Do you want to continue [Y/N] N
OK googbye
hadoop@master:~/shell_test/cin$
demo10
#!/bin/bash
#reading data from file
count=1
cat q | while read line
do
echo "Line $count: $line"
count=$[ $count +1 ]
done
echo Finish processing the data
//result
hadoop@master:~/shell_test/cin$ ./test11
Line 1: #!/bin/bash
Line 2: #getting just one character of input
Line 3:
Line 4: read -n1 -p "Do you want to continue [Y/N] " answer
Line 5: case $answer in
Line 6: Y | y) echo
Line 7: echo "fine ,continue on..." ;;
Line 8: N | n) echo
Line 9: echo "OK googbye"
Line 10: exit ;;
Line 11: esac
Line 12: echo "This is the end of the script"
Line 13:
Finish processing the data
hadoop@master:~/shell_test/cin$
demo 12
getopts 工具获取命令行参数
#!/bin/bash
#processing options and parameters with getopts
while getopts :ab:cd opt
do
case "$opt" in
a) echo "Found the -a option" ;;
b) echo "Found the -b option with the value $OPTARG" ;;
c) echo "Found the -c option" ;;
d) echo "Found the -d option" ;;
*) echo "Unhnown option: $opt" ;;
esac
done
shift $[ $OPTIND -1 ]
count=1
for param in "$@"
do
echo "Parameter $count: $param"
count=$[ $count + 1 ]
done
adoop@master:~/shell_test/cin$ ./test12 -a -b test1 -d test2 test3 test4
Found the -a option
Found the -b option with the value test1
Found the -d option
Parameter 1: test2
Parameter 2: test3
Parameter 3: test4
hadoop@master:~/shell_test/cin$ ./test12 -a -b -d test2 test3 test4
Found the -a option
Found the -b option with the value -d
Parameter 1: test2
Parameter 2: test3
Parameter 3: test4
hadoop@master:~/shell_test/cin$
