2016-05-15

控制脚本/定时执行脚本.sh

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+#!/bin/bash
+
+# testing the at command
+
+at -f 4.sh 22:10

控制脚本/捕捉信号.sh

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+#!/bin/bash
+
+# testing signal trapping
+
+trap "echo 'Sorry! I have trapped Ctrl-C'" SIGINT SIGTERM
+
+echo this is a test program
+
+count=1
+
+while [ $count -le 10 ]
+do
+	echo "Loop #$count"
+	sleep 5
+	count=$[ $count+1 ]
+done

控制脚本/捕捉脚本的退出.sh

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+#!/bin/bash
+
+# trapping the script exit
+
+trap "echo byebye" EXIT
+
+count=1
+while [ $count -le 5 ]
+do
+	echo "Loop #$count"
+	sleep 3
+	count=$[ $count + 1 ]
+done

控制脚本/移除捕捉.sh

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+#!/bin/bash
+
+# removeing a set trap
+
+trap "echo byebye" EXIT
+
+count=1
+while [ $count -le 5 ]
+do
+	echo "Loop #$count"
+	sleep 3
+	count=$[ $count + 1 ]
+done
+#移除捕捉
+trap - EXIT
+echo "I just removed the trap"

理解输入和输出/列出当前脚本打开的文件描述符.sh

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+#!/bin/bash
+
+# testing lsof with file descriptors
+
+exec 3>test
+exec 6>test
+exec 7<test
+
+lsof -a -p $$ -d0,1,2,3,6,7
+
+
+
+
+

理解输入和输出/创建临时目录.sh

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+#!/bin/bash
+
+# using a temporary directory
+
+tempdir=`mktemp -d dir.XXXXXX`
+cd $tempdir
+
+tempfile1=`mktemp temp.XXXXXX`
+tempfile2=`mktemp temp.XXXXXX`
+exec 7> $tempfile1
+exec 8> $tempfile2
+
+echo "Sending data to directory $tempdir"
+echo "This is a test line of data for $tempfile1" >&7
+echo "This is a test line of data for $tempfile2" >&8
+

理解输入和输出/创建本地临时文件.sh

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+#!/bin/bash
+
+# creating and using a temp file
+
+tempfile=`mktemp test.XXXXXX`
+
+exec 3>$tempfile
+
+echo "This script writes to temp file $tempfile"
+
+echo "This is the first line" >&3
+echo "This is the second line" >&3
+echo "This is the last line" >&3
+
+exec 3>&-
+
+echo "Done creating temp file. The contents are:"
+
+cat $tempfile
+
+rm -f $tempfile 2>/dev/null
+

理解输入和输出/创建自己的重定向/从以重定向的文件描述符中恢复.sh

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+#!/bin/bash
+
+#storing STDOUT, then coming back to it
+
+exec 3>&1
+exec 1>test
+
+echo "This should store in output file"
+echo "along with this line"
+
+exec 1>&3
+
+echo "Now things should be back to normal"

理解输入和输出/创建自己的重定向/关闭文件描述符.sh

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+#!/bin/bash
+# testing closing file descriptors
+
+exec 3>test
+echo "This is a test line of data" >&3
+
+# closing file descriptor
+exec 3>&-
+
+echo "This won't work" >&3
+
+cat test
+
+#覆盖前一个test文件
+exec 3>test
+echo "This'll be bad" >&3

理解输入和输出/创建自己的重定向/创建读写文件描述符.sh

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+#!/bin/bash
+# testing inpiut/output file descriptor
+
+exec 3<> test
+read line <&3
+echo "Read: $line"
+echo "This is the test line" >&3

理解输入和输出/创建自己的重定向/创建输入文件描述符.sh

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+#!/bin/bash
+# redirecting input file descriptors
+
+exec 3>&1
+echo "This is the 3 file descriptor" >&3
+
+exec 6>&0
+exec 0<test
+
+count=1
+while read line
+do
+	echo "Line #$count: $line"
+	count=$[ $count+1 ]
+done
+exec 0<&6
+read -p "Are you done now?" answer
+case $answer in
+Y|y) echo "Goodbye";;
+N|n) echo "Sorry, this is the end";;
+esac
+

理解输入和输出/创建自己的重定向/创建输出文件描述符.sh

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+#!/bin/bash
+
+# using an alternative file descriptor
+
+exec 3>test
+
+echo "This should display on the monitor"
+echo "and this should be stored in the file" >&3
+echo "Then this should be back on the monitor"

理解输入和输出/在tmp目录创建临时文件.sh

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+#!/bin/bash
+
+# creating a temp file in /tmp
+
+tempfile=`mktemp -t tmp.XXXXXX`
+
+echo "This is a test file" > $tempfile
+echo "This is the second line of the test" >> $tempfile
+
+echo ”The temp is locate at : $tempfile“
+cat $tempfile
+rm -f $tempfile

理解输入和输出/快速清除文件或日志.sh

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+#!/bin/bash
+
+# 清除日志
+
+cat /dev/null > [Logname]

理解输入和输出/记录信息.sh

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+#!/bin/bash
+
+# using the tee command for logging
+#将输入一边发送到STDOUT，一边发送到日志文件
+tempfile=test
+echo "This is the start of the test" | tee $tempfile
+echo "This is the second line of the test" | tee -a $tempfile
+echo "This is the end line of the test" | tee -a $tempfile
+
+

脚本函数/4.sh

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+#!/bin/bash

脚本函数/new

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+#!/bin/bash
+
+for (( i=1; i<=4; i++ ))
+do
+	touch $i.sh
+	chmod 764 $i.sh
+	echo "#!/bin/bash" > $i.sh
+done

脚本函数/从函数返回数组.sh

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+#!/bin/bash
+
+# returning an array value
+
+function arraydblr {
+	local origarry
+	local newarray
+	local elements
+	local i
+	origarry=(`echo "$@"`)
+	newarray=(`echo "$@"`)
+	elements=$[ $# - 1 ]
+	for (( i=0; i<=$elements; i++ ))
+	{
+		newarray[$i]=$[ ${origarry[$i]} * 2 ]
+	}
+
+	echo ${newarray[*]}
+}
+
+myarray=(1 2 3 4 5)
+echo "The original array is : ${myarray[*]}"
+arg1=`echo ${myarray[*]}`
+result=(`arraydblr $arg1`)
+echo "The new array is : ${result[*]}"

脚本函数/使用return命令.sh

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+#!/bin/bash
+
+# using the return command in a function
+
+function db1 {
+	read -p "Enter a value:" value
+	echo "doubling the value"
+	return $[ $value * 2 ]
+}
+
+db1
+echo "The new value is $?"

脚本函数/使用全局变量带来的问题.sh

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+#!/bin/bash
+
+# demonstrating a bad use of variables
+
+function func1 {
+	temp=$[ $value + 5 ]
+	result=$[ $temp * 2 ]
+}
+
+temlp=4
+value=6
+
+func1
+echo "The result is $result"
+
+if [ $temp -gt $value ]
+then
+	echo "Temp is larger"
+else
+	echo "temp is smaller"
+fi

脚本函数/使用函数输出.sh

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+#!/bin/bash
+# using the echo to return a value
+
+function db1 {
+	read -p "Enter a value:" value
+	echo $[ $value*2 ]
+}
+
+result=`db1`
+echo "The new value is $result"
+

脚本函数/使用命令行中传递的参数.sh

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+#!/bin/bash
+
+# using a global variable to pass a value
+
+function db1 {
+	# $1和$2 不能从命令行中传递，只能调用函数时，手动传递
+	echo $[ $1 * $2 ]
+}
+
+if [ $# -eq 2 ]
+then
+	value=`db1 $1 $2`
+	echo "The result is $value"
+else
+	echo "Usage: badtest1 a b"
+fi

脚本函数/使用局部变量.sh

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+#!/bin/bash
+
+# demonstrating the local keyword
+
+function func1 {
+	local temp=$[ $value +5 ]
+	result=$[ $temp * 2 ]
+}
+
+temp=4
+value=6
+
+func1
+
+echo "The result is $result"
+if [ $temp -gt $value ]
+then
+	echo "temp is larger"
+else
+	echo "temp is smaller"
+fi

脚本函数/使用库函数.sh

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+#!/bin/bash
+
+#using a library file the wrong way
+
+. ./脚本库.sh
+
+result=`addem 10 15`
+echo "The result is $result"

脚本函数/全局变量.sh

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+#!/bin/bash
+
+# using a global variable to pass a value
+
+function db1 {
+	value=$[ $value * 2 ]
+}
+
+read -p "Enter a value: " value
+db1
+echo "The new value is : $value"
+

脚本函数/函数递归.sh

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+#!/bin/bash
+
+function factorial {
+	if [ $1 -eq 1 ]
+	then
+		echo 1
+	else
+		local temp=$[ $1 -1 ]
+		local result=`factorial $temp`
+		echo $[ $result * $1 ]
+	fi
+}
+
+read -p "Please input a value: " value
+result=`factorial $value`
+echo "The factorial of $value is: $result"

脚本函数/在函数中使用参数.sh

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+#!/bin/bash
+
+# passing parameters to a function
+
+function addem {
+	if [ $# -eq 0 ] || [ $# -gt 2 ]
+	then 
+		echo -1
+	elif [ $# -eq 1 ]
+	then 
+		echo $[ $1 + $1 ]
+	else
+		echo $[ $1 + $2 ]
+	fi
+}
+
+echo -n "Adding 10 and 15:"
+value=`addem 10 15`
+echo $value
+
+echo -n "Let's try adding just one number: "
+value=`addem 10`
+echo $value
+
+echo -n "Now trying adding no number: "
+value=`addem`
+echo $value
+
+echo -n "Finally, try adding three or more numbers: "
+value=`addem 10 15 20`
+echo $value
+

脚本函数/基本的脚本函数.sh

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+#!/bin/bash
+
+# using a function in script
+
+function func1 {
+	echo "This is an example of a function"
+}
+
+count=1
+while [ $count -le 5 ]
+do
+	func1
+	count=$[ $count+1 ]
+done
+echo "This is the end of the loop"
+func1
+echo "Now this is the end of the script"

脚本函数/想函数传数组数据.sh

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+#!/bin/bash
+
+# trying to pass an array variable
+
+function testit {
+	echo "The parameters are : $@"
+	
+	#函数只会读取数组变量的第一个值
+	thisarray=$1
+	echo "The received array is ${thisarray[*]}"
+
+	local newarray
+	newarray=(`echo "$@"`)
+	echo "The new array value is : ${newarray[*]}"
+}
+
+myarray=(1 2 3 4 5)
+echo "The original array is : ${myarray[*]}"
+
+#将数组变量当成一个函数参数，函数只会去函数变量第一个值
+#testit $myarray
+
+testit ${myarray[*]}

脚本函数/累加数组中的值.sh

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+#!/bin/bash
+
+#adding values in the array
+
+function addarray {
+	local sum=0
+	local newarray
+	newarray=(`echo "$@"`)
+	for value in ${newarray[*]}
+	do
+		sum=$[ $sum + $value ]
+	done
+	echo $sum
+}
+
+myarray=(1 2 3 4 5)
+echo "The original array is : ${myarray[*]}"
+arg1=`echo ${myarray[*]}`
+result=`addarray $arg1`
+echo "The result is $result"

脚本函数/脚本库.sh

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+#!/bin/bash
+
+# myscript functions
+
+function addem {
+	echo $[ $1 + $2 ]
+}
+
+function multem {
+	echo $[ $1 * $2 ]
+}
+
+function divem {
+	if [ $2 -ne 0]
+	then
+		echo $[ $1/$2 ]
+	else
+		echo -1
+	fi
+}

脚本函数/默认退出状态码.sh

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+#!/bin/bash
+
+# testing the exit status of a function
+
+func1() {
+	echo "Trying to display a non-existent file"
+	ls -l badfile
+}
+
+#由于最后一条命令未执行成功，返回的状态码非0
+echo "testing the function"
+func1
+echo "The exit status is : $?"
+
+func2() {
+	ls -l badfile
+	echo "Another test to display a non-existent file"
+}
+
+#由于最后一条命令echo执行成功，返回的状态码为0
+echo "Another test"
+func2
+echo "The exit status is : $?"
+
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