What is wrong with my DOB Sorting script - bash

Question

I keep getting an error on line 22: [!: command not found
My script Asks for a name, phone number, and date of birth and then amends these details to a comma separated value file called “birthday.csv”.
It then Sorts “birthday.csv” by date of birth. The newly sorted file is then displayed and calculates their age.
Can someone take a look at my script and see why this is popping up.
#!/bin/bash
a=0
while [ $a -lt 2 ];
do
echo Please enter a first name
read firstName
echo Please enter last name
read lastName
echo Please enter phone number
read phoneNumber
echo Please enter date of birth - format dd/mm/yyyy
read dob
echo "$firstName,$lastName,$phoneNumber,$dob" >> userBirthdays.csv
echo If you would like to add another person press 1 or enter 2 to proceed
read a
done
INPUT=./userBirthdays.csv
OLDIFS=$IFS
IFS=","
[! -f INPUT] & while read Name Surname Telephone DOB
do
birthMonth=${DOB:0:2}
birthDay=#10${DOB:3:2}
birthYear=${DOB:6:4}
currentDate=`date +%d/%m/%Y`
currentMonth=${currenDate:0:2}
currentDay=#10${currentDate:3:2}
currentYear=${currentDate:6:4}
if [[ "$currentMonth" -lt "$birthMonth" ]] || [[ "$currentMonth" -eq "$birthMonth" && "$((#10$currentDay))" -lt "$((#10$birthDay))" ]]
then
let Age=currentYear-birthYear-1
else
let Age=currentYear-birthYear
fi
echo "Name : $Name"
echo "Surname : $Surname"
echo "Telephone : $Telephone"
echo "DOB : $DOB"
echo "Age : $Age"
echo "##########################################"
done < $INPUT
IFS=$OLDIFS
echo $DATE
exit 0;
Thank you in advance

Answer 1

you need a space between between the [ and ! chars, i.e.
[ ! -f $INPUT ] && while read ....
#^-^--------^-^---^------------
Note that you almost certainly want two '&' chars, as in my correction.
Thanks to #GordonDavisson for another '$' ;-)
IHTH

Answer 2

Separate [ and ! with a space, so [ will be a command, and ! will be its first argument, as you meant them to be.
(Not sure there are no other problems).