幾個腳本

查看用戶的默認shell

#!/bin/bash
read -p "please type in the user name:" USER
 if cat /etc/passwd | cut -d: -f1 |grep ^$USER$ &> /dev/null ;then
      cat /etc/passwd |cut -d: -f1,7 |grep $USER |cut -d: -f2
       else
 echo "do not exist "
   fi

3個數求最大值

#!/bin/bash
let SUM=0
for I in {1..100}    ; do
A=` echo "$I%2"| bc`
if [ $A -eq 0 ];then
 let SUM+=$I
else
continue
fi
done
echo "the sum is $SUM"

修改ip

#!/bin/bash
ifconfig | grep "inet addr" |grep -v "127.0.0.1"
read -p "please type in the ip addr" IP
read -p "please type in the ip mask" MASK
sed -i s/^BOOTPROTO.*/BOOTPROTO=static/g /etc/sysconfig/network-scripts/ifcfg-eth0
sed -i -e 's/IPADDR/#IPADDR/g' -e 's/NETMASK/#NETMASK/g' /etc/sysconfig/network-scripts/ifcfg-eth0
sed -i /BOOTPROTO/aIPADDR=$IP /etc/sysconfig/network-scripts/ifcfg-eth0
sed -i /BOOTPROTO/aNETMASK=$MASK /etc/sysconfig/network-scripts/ifcfg-eth0
. /etc/sysconfig/network-scripts/ifcfg-eth0
ifconfig | grep "inet addr" |grep -v "127.0.0.1"

pingc/b類ip地址（c類以192.168.0.0網段b類以172.16.0.0網段）

#!/bin/bash
read -p "plesae type in the b/c net " NET
if [ $NET = b  -o  $NET = B ];then
 echo "this a b net"
for I in {1..255};do
  for R in {1..255};do
    if ping -c1 -W2 172.16.$I.$R &> /dev/null ;then
      echo "$I.$R is online."
    else
      echo "$I.$R is offline."
  fi
 done
 done
 elif [ $NET = c  -o  $NET =  C ];then
 echo "this is a c net"
  for I in {1..255};do
 if ping -c1 -W2 192.168.0.$I &>/dev/null ;then
  echo"$I is online"
 else
  echo "$I is offline."
  fi
 done
else
  echo "u r stu"
fi 

求100之類偶數和

#!/bin/bash
let SUM=0
for I in {1..100}    ; do
A=` echo "$I%2"| bc`
if [ $A -eq 0 ];then
 let SUM+=$I
else
continue
fi
done
echo "the sum is $SUM"