Functions and arrays

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

[[email protected] test]#  echo -e "\033[31m FAILED \033[0m"
 FAILED 
[[email protected] test]#  echo -e "\033[32m ok \033[0m"
 ok 
#!/bin/bash
read -p "please input arg:" arg
color() {
if [ $# -ne 0 ];then
        echo -e "\033[31m OK \033[0m"
else
        echo -e "\033[32m FAILED \033[0m"
fi
}

color $arg
[[email protected] test]# chmod a+x color.sh
[[email protected] test]# ./color.sh
please input arg:
 FAILED 
[[email protected] test]# ./color.sh
please input arg:1
 OK 

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

#!/bin/bash

read -p "please input arg:" arg
func() {
if [ $# -ne 0 ];then
  echo $arg
else
  echo " error "
fi
}

func $arg 
[[email protected] test]# chmod a+x 6.2.sh

[[email protected] test]# ./6.2.sh
please input arg:1
1
[[email protected] test]# ./6.2.sh
please input arg:
 error 

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

[[email protected] test]# vim 6.3.sh
#!/bin/bash

read -p "please input two num:" a b
func() {
if [ $a -gt $b ];then
  echo " The maximum value is $a"
elif [ $b -gt $a ];then
  echo " The maximum value is $b"
else
  echo " equal "
fi
}

func $a $b

[[email protected] test]# chmod a+x 6.3.sh
[[email protected] test]# ./6.3.sh
please input two num:5 8
 The maximum value is 8
[[email protected] test]# ./6.3.sh
please input two num:9 3
 The maximum value is 9
[[email protected] test]# ./6.3.sh
please input two num:6 6
 equal 

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

[[email protected] test]# vim 6.4.sh
#!/bin/bash
read -p "please input two num:" a b
func () {
[ $# -ne 2 ] && {
  echo "usage: $0 num1 num2"
  exit 1
}
expr $a + $b  &> /dev/null
if [ $? -ne 0 ]
then
  echo "you must input two number" 
  exit 2
fi
echo "$a+$b=$(($a+$b))" 
echo "$a-$b=$(($a-$b))" 
echo "$a*$b=$(($a*$b))" 
echo "$a/$b=$(($a/$b))"
}

func $a $b

[[email protected] test]# chmod a+x 6.4.sh
[[email protected] test]# ./6.4.sh
please input two num:3 4
3+4=7
3-4=-1
3*4=12
3/4=0
[[email protected] test]# ./6.4.sh
please input two num:w r
you must input two number

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

[[email protected] test]# vim 6.5.sh
#!/bin/bash
declare -a array
i=0
while read line
do
  array[$i]=$line
  echo ${array[$i]}
  let i++
done < /etc/shadow

[[email protected] test]# chmod a+x  6.5.sh

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

[[email protected] test]# vim 6.6_7.sh
#!/bin/bash
declare -A array
for i in `cut -d: -f 7 /etc/passwd`
do
  let array[$i]++
done
for i in ${!array[*]}
do
  echo "$i ${array[$i]}"
done
[[email protected] test]# chmod a+x 6.6_7.sh
[[email protected] test]# ./6.6_7.sh
/sbin/nologin 35
/bin/bash 23
/sbin/halt 1
/bin/sync 1
/sbin/shutdown 1

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

[[email protected] test]# vim 6.7_1.sh
#!/bin/bash
read -p "please iuput dir:" d
declare -A array
for i in `ls -F $d | grep -v /$ | fgrep . | cut -d . -f 2`
do
  let array[$i]++
done
for i in ${!array[*]}
do
  echo "$i ${array[$i]}"
done
[[email protected] test]# chmod a+x 6.7_1.sh
[[email protected] test]# ./6.7_1.sh
please iuput dir:/root/
cfg 1
sh 1