Shell--- function

1. Write function , Achieve green printing OK And red FAILED, Determine whether there are parameters , Existence as OK, There is no such thing as FAILED;

The script is written as follows ：

[[email protected] ~]# cat color.sh 
#!/bin/bash
##############################################################
# File Name: color.sh
# Version: V1.0
# Author: xx
# Email: [email protected]
# Organization: http://www.xx.com/xx/
# Created Time : 2022-07-18 14:50:00
# Description:
##############################################################

color()
{
	if [ ! -z "$1" ];then
		echo -e "\033[32m ok \033[0m"
	else
		echo -e "\033[31m FAILED \033[0m"
	fi
}
color $1

The results are as follows ：

[[email protected] ~]# ./color.sh a
 ok                                     //  here shell The display in is green 
[[email protected] ~]# ./color.sh 
 FAILED                                 //  here shell The display in is red 

#： How to print font colors ：

2. Write function , To judge whether there is no position parameter , If there are no parameters , Prompt error

[[email protected] ~]# cat wc.sh 
#!/bin/bash
##############################################################
# File Name: wc.sh
# Version: V1.0
# Author: xx
# Email: [email protected]
# Organization: http://www.xx.com/xx/
# Created Time : 2022-07-18 15:25:28
# Description:
##############################################################

weican()
{
	if [ $# -eq 0 ];then
		echo "error"
	else
		echo "right"
	fi
}
weican $1

The results are as follows ：

[[email protected] ~]# chmod 755 wc.sh 
[[email protected] ~]# ./wc.sh 
error
[[email protected] ~]# ./wc.sh a
right
[[email protected] ~]#

#： Positional arguments ：“ The so-called position parameter is 0,1,2,3,4,5,6,7,8,9.... When using , use $0,$1,$2.... The position parameter is when script When loaded , The parameters attached later .

3. Write a function to implement two numbers as parameters , Return maximum

[[email protected] ~]# cat max.sh 
#!/bin/bash
##############################################################
# File Name: max.sh
# Version: V1.0
# Author: xx
# Email: [email protected]
# Organization: http://www.xx.com/xx/
# Created Time : 2022-07-18 15:38:14
# Description:
##############################################################

read -p "please input:" num1 num2
max_b()
{
	if [ $num1 -gt $num2 ];then
		echo "max is $num1"
	elif [ $num1 -lt $num2 ];then
		echo "max is $num2"
	else
		echo "$num1 equals $num2"
	fi	
}
max_b $num1 $num2

The results are shown below ：

[[email protected] ~]# chmod 755 max.sh
[[email protected] ~]# ./max.sh 
please input:12 23
max is 23

4. Write function , Implement two integer digit parameters , Calculate addition, subtraction, multiplication and division .

[[email protected] ~]# cat js.sh 
#!/bin/bash
##############################################################
# File Name: js.sh
# Version: V1.0
# Author: xx
# Email: [email protected]
# Organization: http://www.xx.com/xx/
# Created Time : 2022-07-18 15:48:56
# Description:
##############################################################

read -p "please input your number:" num1 num2
cu()
{
	expr $num1 + $num2 &> /dev/null 
	if [ $? -ne 0 ];then
		echo "please input two interger numbers"
	else
		echo "$num1+$num2=$((num1+num2))"
		echo "$num1-$num2=$((num1-num2))"
		echo "$num1*$num2=$((num1*num2))"
		echo "$num1/$num2=$((num1/num2))"
	fi
}
cu $num1 $num2

The results are as follows ：

[[email protected] ~]# ./js.sh 
please input your number:8 2
8+2=10
8-2=6
8*2=16
8/2=4
[[email protected] ~]# ./js.sh 
please input your number:asd
please input two interger numbers
[[email protected] ~]# ./js.sh 
please input your number:1
please input two interger numbers
[[email protected] ~]#

5. take /etc/shadow Each line of the file is assigned to the array as a primitive

[[email protected] ~]# cat au.sh 
#!/bin/bash
##############################################################
# File Name: au.sh
# Version: V1.0
# Author: xx
# Email: [email protected]
# Organization: http://www.xx.com/xx/
# Created Time : 2022-07-18 16:06:22
# Description:
##############################################################

declare -a array
i=0
while read input
do
	array[$i]=$input
	echo ${array[$i]}
	let i++
done < /etc/passwd

The results are as follows ：

[[email protected] ~]# chmod 755 au.sh 
[[email protected] ~]# ./au.sh 
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync

6. Use associative array statistics file /etc/passwd Different types used by users in shell The number of

[[email protected] ~]# cat gs.sh 
declare -A shells
while read input
do
	type=`echo $input | awk -F: '{print $NF}'`
	let shells[$type]++
done < /etc/passwd
for i in ${!shells[*]}
do
	echo "$i : ${shells[$i]}"
done

The results are shown below ：

[[email protected] ~]# chmod 755 gs.sh
[[email protected] ~]# ./gs.sh 
/sbin/nologin : 22
/bin/sync : 1
/bin/bash : 4
/sbin/shutdown : 1
/sbin/halt : 1

7. Use the associative array to count the number of files in the specified directory by extension

declare -A array
num=`find /root/shell/test* -type d | wc -l`
for ((i=0;i<$num;i++))
do
  type=`find /root/shell/test* -type d | head -$[$i+1] | tail -1`
  array[$type]=`find $type -type f | wc -l`
done
for i in ${array[*]}
do
  echo "$i : ${array[$i]}"
done