for

#!/bin/bash

sum=0
for num in 1 2 3 4 5　　注释：可以把in后的数字用$@代替，接收从键盘输入
        do
                sum=$((sum+num))
        done

echo "sum=$sum"

#!/bin/bash
#批量解压缩

cd 目录
ls *.tar.gz>tmp.txt
for i in $(cat tmp.txt)
    do
        tar -xzf $i &>/dev/null
    done
rm -rf 目录/tmp.txt

for((i=1;i<=100;i=(($i+1))))　　注释：(($i+1))可以直接写成i+1
        do
                sum=$(($sum+$i))
        done
echo "sum=$sum"

[root@localhost ~]# ./myShell.sh 
sum=5050

#!/bin/bash
#批量添加用户
read -p "请输入用户名前缀：" -t 20 namePrefix
read -p "请输入用户数量:" -t 20 num
read -p "请输入用户密码：" -t 20 pass
if[ ! -z $name -a ! -z $num -a ! z $pass ]
    then
        n=$(echo $num|sed ‘s/[0-9]//g‘)
            if[ -z $n ]
                then
                    for((i=1;i<=$num;i=i+1))
                        do
                            /usr/sbin/useradd $namePrefix$i &>/dev/null
                            echo $pass|/usr/bin/passwd --stdin $namePrefix$i &>/dev/null
                        done
            fi
fi