Linux user script creation/guessing game/network card traffic monitoring introduction

#!/bin/bash
USERADD(){ #User created function RN=$(sed -n '$=' $1)
        for ((I=1;I<=$RN;I++))
        do
                user=`sed -n "$I"p $1`
                password=`sed -n "$I"p $2`

                id $user &>/dev/null # Check if the user exists [ $? -eq 0 ] && {
                        echo "$user already exists"
                }||{
                        useradd $user #Create a new user in $user echo "$password" | passwd --stdin $user &> /dev/null
                        [ $? -eq 0 ] && {
                                echo "$user user created successfully"
                        }
                }
        done
}
# Judgment module [ $# -lt 2 ] && { #Judge whether the file is less than two echo "ERROR: Insufficient number of files!!"
}||{ [ -e $1 -a -e $2 ]&& { #Judge whether the file exists #Judge whether the number of lines of two files are equal [ `sed -n '$=' $1` -eq `sed -n '$=' $2` ] &&{
                        USERADD $1 $2
                        #Call user created function}||{
                        echo "ERROR: The number of lines in the file is inconsistent!!"
                }
        }||{
                echo "ERROR: The file does not exist!!"
        }
}

#!/bin/bash

Number=7
while true
do
       read -p "Please enter a number: " NUM
       if [ $NUM = $Number ]
       then
               echo "Congratulations, you guessed it right!!!"
               exit
       elif [ $NUM -lt $Number ]
       then
               echo -n "The number is too small!"
       elif [ $NUM -gt $Number ]
       then
               echo -n "The number is too large!"
       else
               echo -n "error"
       fi
done

#!/bin/bash

[ -z $* ] && {
        echo "ERROR: Not input net device!"
}||{
        Device=`ifconfig $* 2> /dev/null`&&{
                while true
                do
                        RXpre=$(cat /proc/net/dev | grep $1 | tr : " " | awk '{print $2}')
                        TXpre=$(cat /proc/net/dev | grep $1 | tr : " " | awk '{print $10}')
                        # Get the traffic received and sent by the network port after 1 second sleep 1
                        RXnext=$(cat /proc/net/dev | grep $1 | tr : " " | awk '{print $2}')
                        TXnext=$(cat /proc/net/dev | grep $1 | tr : " " | awk '{print $10}')
                        # Get the actual inbound and outbound traffic in this 1 second RX=$((${RXnext}-${RXpre}))
                        TX=$((${TXnext}-${TXpre}))

                        TX=$(echo $TX | awk '{print $1/1024 " KB/s "}')
                        RX=$(echo $RX | awk '{print $1/1024 " KB/s "}')
					
					#Refresh the monitoring display on the same line #echo -ne "input: $RX \t\toutput: $TX "
                        #echo -ne "\r"
					clear # Use clear to clear the screen and then display echo -ne "input: $RX \noutput: $TX "					   
                done
        }||{
                echo "$1 is not exist"
        }
}