2014马哥Linux0217-2中的脚本题目

0217-2课中，马哥除了几道题目，我把答案写在这里，但是有些表述和马哥的是不一样的，但只是表述区别，结果是一样的：

练习：计算100以内所有正整数之和

#!/bin/bash

sum=0

for i in `seq 1 100`;do

sum=$[$sum+$i]

done

echo "The sum of 1+..+100 is $sum."

练习：分别计算100以内所有偶数之和和奇数之和：

#!/bin/bash

oddSum=0

evenSum=0

for i in `seq 1 2 100`;do

oddSum=$[$oddSum+$i]

done

echo "The oddsum is $oddSum."

for j in `seq 2 2 100`;do

evenSum=$[$evenSum+$j]

done

echo "the evensum is $evenSum."

练习：计算当前系统所有用户的ID之和：

#!/bin/bash

uidSum=0

for userName in `cut -d: -f1 /etc/passwd`;do

uidSum=$[$uidSum+`id -u $userName`]

done

echo "The sum of UID of all users' is $uidSum."

练习：计算/etc/rc.d/rc.sysinit、/etc/init.d/functions和/etc/issue三个文件的字符数

之和

#!/bin/bash

wordSum=0

for fileName in /etc/rc.d/rc.sysinit /etc/init.d/functions /etc/issue;do

wordSum=$[$wordSum+`wc -c $fileName | cut -d" " -f1`] #注意要cut

done

echo "The sum of characters of three files is $wordSum."

练习：新建用户tmpuser1-tmpuser10，并计算他们的ID之和：

#!/bin/bash

uisSum=0

for i in `seq 1 10`;do

useradd tmpuser$i

echo "User tmpuser$i has been created."

uidSum=$[$uidSum+`id -u tmpuser$i`]

done

echo "The sum of UID newly created is $uidSum."

这几题都是自己写出来的，是在复习的过程中写的。希望记忆深刻点，别下周就忘记了。