判断192.168.1.0/24网络中,当前在线的ip有哪些
需求:判断192.168.1.0/24网络中,当前在线的ip有哪些,并编写脚本打印出来。
[root@openEuler ~]# cat 1.sh
#!/bin/bash
for ip in $(seq 1 254); do
ping -c 1 -W 1 "192.168.1.$ip" > /dev/null 2>&1
if [ $? -eq 0 ]; then
echo "192.168.1.$ip is online"
fi
done
设计一个 Shell 程序,在/userdata 目录下建立50个目录,即 user1~user50,并设置每个目录的权限,其中其他用户的权限为:读;文件所有者的权限为:读、写、执行;文件所有者所在组的权限为:读、执行。
[root@openEuler ~]# cat 2.sh
#!/bin/bash
mkdir -p /userdata
for i in {1..50}; do
dir="/userdata/user$i"
mkdir -p "$dir"
chmod 754 "$dir"
echo "Created and set permissions for $dir"
done
结果
[root@openEuler ~]# sh 2.sh
[root@openEuler ~]# ll /userdata
total 200
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_1
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_10
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_11
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_12
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_13
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_14
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_15
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_16
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_17
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_18
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_19
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_2
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_20
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_21
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_22
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_23
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_24
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_25
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_26
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_27
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_28
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_29
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_3
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_30
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_31
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_32
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_33
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_34
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_35
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_36
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_37
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_38
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_39
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_4
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_40
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_41
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_42
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_43
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_44
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_45
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_46
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_47
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_48
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_49
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_5
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_50
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_6
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_7
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_8
drwxr-xr-- 2 root root 4096 Jan 14 08:47 user_9