How to run 'join' command for multiple files (of 2 types) in a folder I have two types of files for a gene in a folder

File 1: FOS.tf.txt 

ABL2
ACTN4
ADGRE5
ADIPOR2
ADRB2
ERCC4
EZR
FAS
FMO4


File 2: FOS.tt.txt

ABL2
CASP9
CCK
DDIT3
ERCC4
EZR
FAS
FMO4


After running command 

join FOS.tf.txt FOS.tt.txt &gt; FOS_final.txt


I got output file: FOS_final.txt

ABL2
ERCC4
EZR
FAS
FMO4


My question is that I have these two type of files (tf and tt) for 605 genes in a folder and I want to run join command together for all my genes and get 605 output files.
If all of your .tf.txt and .tt.txt files are in the same directory, the following command should work.

for tffile in $(ls *.tf.txt)
do
    prefix=$(basename $tffile .tf.txt)
    join ${prefix}.tf.txt ${prefix}.tt.txt &gt; ${prefix}_final.txt
done