1.判断字符串是否为空
#!/usr/bin/bash
while : #:默认值为真
do
read -p "请输入你的密码: " a
pass=123456
if [ -z $a ];thenecho "您输入的密码不能为空"exit 1
elseif [ $a = $pass ];thenecho "登录成功"breakelseecho "您的密码输入有误，请重新输入"fi
fi
done
2.判断文件是否存在
#/bin/bash
if [ -f /opt/a.txt ];thenecho "ok"
elseecho "不存在,正在创建"touch /opt/a.txt
fi
3.必须在脚本后加上适当的参数脚本才能正确执行
#!/bin/bash
if [ "$1" = "hello" ]; thenecho "Hello! How are you ?"
elif [ "$1" = "" ]; thenecho "You MUST input parameters"
elseecho "The only accept parclear ameter is hello"
fi
4.测试ip地址主机位从2到100的机器是否存活，并把存活的机器记录到文本文件alivehost.txt内。(使用ping命令)
#!/usr/bin/bash
src_ip="192.168.246"
for i in {2..254}
do{ping -c1 $src_ip.$i &>/dev/nullif [ $? -eq 0 ];thenecho "alive: $src_ip.$i" >> ip_up.txtecho "alive: $src_ip.$i"elseecho "down: $src_ip.$i" >> ip_down.txtecho "down: $src_ip.$i"fi} &
done
wait
echo "finish..."
5.根据用户输入foo打印bar，输入bar打印foo，否则输入只能输入foo|bar
#!/usr/bin/env bash
case $1 infoo)echo "bar";;bar)echo "foo";;*)echo "Usage:$0 '{foo|bar}'";;
esac
6.随机数生成8位随机密码
#!/bin/bash
string="AFJALKGJglekrjgkASKJFEKFELjjglkerjgwej235834095ejglkdjg"
sum=''
for ((i=1; i<=8; i++)) #指定循环8次
dolen=${#string} #获取变量的长度num=$[RANDOM % $len] #使用变量长度中生成随机数（作为取字符的索引）value=${string:$num:1} #截取指定索引的字符sum+=$value #字符追加到sum变量中
done
echo $sum
7.for循环批量创建用户
#!/usr/bin/bash
read -p "请设置用户名/数量/密码: " prefix num pass
cat <<-EOF
用户前缀:$prefix
用户数量:$num
用户密码:$pass
EOF
for i in $(seq 1 $num)
do
user=$prefix$i
id $user &> /dev/null
if [ $? -eq 0 ];thenecho "$user is already exist!"exit 0
elseuseradd $user &> /dev/null && echo $pass | passwd --stdin $user &>/dev/null
fi
done
echo "starting create users..."
8.通过一个文件批量创建用户：
#背景：写一个脚本，满足以下需求及应用，如一个文件的内容如下，根据文件内容实现批量创建用户，第一列为用户名，第二列为密码
[root@localhost script]# vim user_pass.txt #创建用户和密码文件
user1 123456
user2 654321
user3 1122334
user4 4433221
user5 9876543
[root@localhost script]# vim create_user.sh #编写脚本
#!/usr/bin/bash[ $UID -ne 0 ] && exit 1
while read line
douser=`echo $line | awk '{print $1}'`pass=`echo $line | awk '{print $2}'`id $user &> /dev/null || useradd $user && echo $pass | passwd $user --stdin
done < /opt/test/script/user_pass.txt
9.随机数实现猜数字游戏
#!/bin/bash
num=$[RANDOM % 10]
i=1 #定义i为循环条件
a=0 #定义a为猜的次数变量
while [ $i -eq 1 ]
do
read -p "请输入你猜的数字（0~10）：" cif [ $c -eq $num ];thenecho "恭喜你猜对了！"let a++let i++elif [ $c -gt $num ];thenecho "你猜高了，请继续！"let a++elif [ $c -lt $num ];thenecho "你猜低了，请继续！"let a++fi
done
echo "你一共猜了${a}次。"
10.建立ssh免密连接脚本
[root@mysql-server script]# cat shuzu.sh
#!/bin/bash
server_ip=(192.168.209.166 192.168.209.168 192.168.209.169)
server_name=(web-1 web-2 mysql-server)
for (( i=0; i<${#server_ip[@]}; i++ ))
doecho $i-----${server_ip[i]}-----${server_name[i]}
done
echo "请输入要连接的序号: " && read n
if [[ $n -ge 0 && $n -lt ${#server_ip[@]} ]];thenecho "正在链接${server_ip[n]}"sleep 1/root/expect/expect.sh ${server_ip[n]}
elseecho "请输入范围内的序号..."sleep 1
fi
/root/expect/expect.sh
#!/usr/bin/expect
set user root
set pass 1
set ip [ lindex $argv 0 ]
set timeout 10spawn ssh $user@$ip
expect {"yes/no" { send "yes\r"; exp_continue }"password:" { send "$pass\r" };
}
interact
