Linux-for

for 变量 in 列表;

循环体

done

如何生成列表；

{1..100}

seq [起始数][步长]结束值；

#!/bin/bash

lines=`cat /etc/passwd |wc -l`

for i in `seq 1 $lines`;

do

        user=`cut -d: -f1 /etc/passwd | head -$i | tail -1`

        echo "hello:$user"

done

输出shell为bash的用户

#!/bin/bash

lines=`cat /etc/passwd |wc -l`

for i in `seq 1 $lines`;

do

#user=`cut -d: -f1 /etc/passwd`

        user=`cut -d: -f1 /etc/passwd | head -$i | tail -1`

        shell=`cut -d: -f7 /etc/passwd | head -$i | tail -1`

if  grep '\<bash\>' $shell &>/tmp/out.txt ;then

        echo "hello:$user,your shel:$shell"

fi

done

添加删除十个用户

#!/bin/bash

#

if [ $1 == add ]&>/tmp/out.txt ;then

        for i in {1..10};do

        useradd $i

        done

        echo "useradd finish"

elif [ $1 == del ]&>/tmp/out.txt ;then

        for i in {1..10};do

        userdel -r $i

        done

        echo "userdell finish"

else

echo "please  use add or del"

fi

判断ESTABLEISHED和LISTEN的个数

#!/bin/bash

#

declare -i estab=0

declare -i listen=0

declare -i other=0

for stat in $(netstat -tan | grep '^tcp\>' | awk '{print $NF}');do

echo $stat

        if [ "$stat" == 'ESTABLISHED' ];then

        let estab++

        elif  [ "$stat" == 'LISTEN' ];then

        let listen++

        else

        let other++

        fi

done

echo $estab

echo $listen

echo $other

判读路径下所有文件的类型

#!/bin/bash

#

for file in `ls /var`; do 

        if [ -f /var/$file ];then

        echo "Common file."

        elif [ -L /var/$file ];then

        echo "Symbolic file"

        elif [ -d /var/$file ];then

        echo "Directory"

        else

        echo "Other type"

        fi

done

判断服务器网络是否能ping通

#!/bin/bash

#

echo "" >/root/ping.log

for i in `seq 1 15`;do

        ping -w 1 172.16.6.$i&>/dev/null 

        if [ $? -eq 0 ];then

        echo "172.16.6.$i is online" | tee -a /root/ping.log

        else

        echo "172.16.6.$i is down" | tee -a /root/ping.log

        fi

done

echo "online is `cat ping.log | grep online | wc -l`"

echo "down is `cat ping.log | grep down | wc -l`" 

打印菱形

#!/bin/bash

#

let number=$1%2

if [  $number -eq 0 ];then

 echo "Please enter odd Numbers"

else

let kk=$1/2

let hh=1

for ((i=1;i<=$1;i+=2));do

   for((k=1;k<=$kk;k++));do

        echo -e -n " "

   done

        for ((y=1;y<=$i;y++));do

        echo -e -n "*"

        done

        echo

let kk-=1

done

for ((j=$1-2;j>=1;j-=2));do

   for((h=1;h<=$hh;h++));do

        echo  -e -n " "

   done

        for ((x=1;x<=$j;x++));do

        echo -e -n "*"

        done

        echo

let hh+=1

done

fi

     本文转自阿伦艾弗森 51CTO博客，原文链接：http://blog.51cto.com/perper/1947649，如需转载请自行联系原作者