is it possible to simply add text to the bottom of multiple files or even one?

for example let's say I want to add to the bottom of several files:

<?php include("../includes/footer.php"); ?> to the bottom of 1.php

echo '<?php include("../includes/footer.php"); ?>' > 1.php

that would result in over writing the entire file

cat 1.php
 <?php include("../includes/footer.php"); ?>


I've checked around and there seems to be no append option

was thinking I could make a python script to do it for me but thought I'd run it by you guys see if you had any ideas. There are times when I want to do stuff along these lines and just want to find the right 'approach' to solving the problem

also I imagine there exists some command in bash that would work much better, thanks in advance.

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Mike Hoy