Shell Basics Using Notes

Create 10 user user1-user10;
[Email protected] ~]# vim user.sh
#!/bin/bash #注释为bash
For ((i=1;i<=10;i++))#条件
Do #动作
Useradd user$i # Add user, $i as variable (i=i+1, always execute to i<=10)
echo "User$i" | passwd--stdin user$i #打印出来, create user password consistent with user name

echo "Jiejie" | passwd--stdin user10# to the user user10 password for Jiejie;
Done #完成

[Email protected] ~]# vim file.sh
#!/bin/bash
Touch file{10 . #创建10个空文件file10-file19

Print 99 multiplication table
[Email protected]Mini ~]# vim multiplicationtable.sh
#!/bin/bash
For ((i=1;i<=9;i++))#条件语句

Do
For ((j=1;j<= $i; j + +))#条件语句
Do
ECHO-E-N "$j * $i =$[$i * $j]\t" #显示以行为首
Done
echo ""
Done

[email protected] ~]#Vim passwd.sh
#!/bin/bash
Read-p "Please input your password >" num #交互式
echo "Your password $num"

Every two hours every day take all the information in the current system/proc/meminfo file to the/stats/memory.txt file
[[Email protected]Mini ~]# Mkdir/stats; Touch Memory.txt
[[Email protected]Mini ~]# CRONTAB-E
1 */2 * * * grep-e "^s"/proc/meminfo >>/stats/memory.txt


Write a script that uses the ping command to detect the online status of all hosts between 192.168.0.1-192.168.0.254;
The online host uses green display;
#!/bin/bash
Ipaddr= "192.168.0."
For i in {1..254}
Do
Ping-c 1 $ipaddr $i &>/dev/null;
If [$?-eq 0]
Then
Echo-e "\e[1;32m$ipaddr$i\e[0m"
Else
Echo-e "\e[1;41m$ipaddr$i\e[0m"
Fi
Done
echo Options:
When using the-e option, if the following characters appear in the string, they are handled in particular, not as general text output:
\a issued a warning sound;
\b Delete the previous character;
\c finally not add the line break symbol;
\f the line but the cursor remains in its original position;
\ n Wraps and the cursor moves to the beginning of the line;
\ r The cursor moves to the beginning of the line, but does not wrap;
\ t Insert tab;
\v is the same as \f;
\ \ insert \ character;
\NNN inserts the ASCII character represented by the NNN (octal);

Read option

-P: Specifies the prompt to read the value;

-T: Specifies the time to wait (in seconds) to read the value

Shell Basics Using Notes