Finding linux users with a bash script

i am newbie in bash-scripting and linux. I want to write a script to get a username from the terminal and say whether that username is on the passwd or not. i wrote and tried below script but it doesn’t work. help me that what i can do.

users = cat /etc/passwd
echo User_Name
cat users | grep User_Name
if [ User_Name in users ];
then
    echo "User_Name FOUND"
else
    echo "User NOT FOUND!"
fi

how i can define a variable to read a string from termnial.

Answer

To print and read an argument from terminal, you should use echo and then use read commane and then call it with dollar-sign, finally the script know what you want. for example:

echo "Enter UserName: "
read User_Name

here is the correct form of your code:

echo "Enter the Username: "
read User_Name
cut -f 1 -d: /etc/passwd | grep -q $User_Name
if [ $? -eq 0 ];
then
    echo "User $User_Name FOUND"
else
    echo "User NOT FOUND!"
fi

---

Tips:

cut -f 1 -d  #cut the first column of the passwd list
grep -q # find username and do  not  write  anything  to  standard   output in terminal.

if [ $? -eq 0 ] #in linux terminal when we want to know whether the previous command is executed correctly we use $? and the output must be 0. and - eq means equal to 0. and when we use that, it means if previos command (grep the username) executed correctly and the username was found, then run next step and print it found.