bash script to change home directory

[packets]

I was task to change the home dir of the thousand of users in my server. The new directory will be according to the first letter of their username. If my username is nelson, the home dir must be /emails/n/nelson. If the login name is fred, the home dir must be /emails/f/fred.

As of the moment, current dir was only located at /home dir such as /home/fred.

Can anyone give a hint on how would I do this? My problem is getting the first character of their username and putting it in their designate folder which was also according to the first characted of their domain.

I tried this script but I encounter a problem

#!/bin/bash

USER=`cat /etc/passwd | grep home | awk -F: '{print $1}'`
LETTER=`cat /etc/passwd | grep home | sed -r 's/(.)[^.]*\.?/\L\1/g'`

for letter in $LETTER;do
for user in $USER;do
if [ "$letter" == t ]; then
mkdir /emails/$letter/$user
mkdir /emails/$letter/$user/Maildir
mkdir /emails/$letter/$user/Maildir/new
mkdir /emails/$letter/$user/Maildir/cur
mkdir /emails/$letter/$user/Maildir/tmp
echo "CHECKING T"
usermod -d /emails/$letter/$user $user
elif [ "$letter" == n ]; then
mkdir /emails/$letter/$user
mkdir /emails/$letter/$user/Maildir/new
mkdir /emails/$letter/$user/Maildir/cur
mkdir /emails/$letter/$user/Maildir/tmp
usermod -d /emails/$letter/$user $user
echo "CHECKING N"
fi

done


done

[cfajohnson]

while IFS=: read user junk
do
  udir=/emails/${user:0:1}/$user
  mkdir -p "$udir/"{new,cur,tmp}
  usermod -d "$udir" "$user"
done < /etc/passwd