for循环

for循环
语法一：

for 变量 in 值1 值2 值3...
do
程序
done

#!/bin/bash
for time in morning noon afternoon evening
do
echo "This is time $time"
done

cd /lamp
ls *.tar.gz > ls.log
for i in $(cat ls.log)
do
tar -zxf $i &>/dev/null
done

rm -rf /lamp/ls.log

语法二：
for((初始值;循环控制条件;变量变化))
do
程序
done

#!/bin/bash
s=0
for ((i=1;i<=100;i=i+1))
do
s=$(($s+$i))
done
echo "1+2+3+...+100 is："$s

批量添加用户
read -p "Please input user name: " -t 30 name
read -p "Please input the number of users: " -t 30 num
read -p "Please input the passwoed of users: " -t 30 pass

if [ ! -z "$name" -a ! -z "$num" -a ! -z "pass" ]
then
y=$(echo $num | sed 's/^[0-9]*$//g')
if [ -z "$y" ]
then
for (( i=1;i<=$num;i=i+1 ))
do
/usr/sbin/useradd $name$i &>/dev/null
echo $pass | /usr/bin/passwd --stdin $name$i &> /dev/null
done
fi
fi