What are the differences in syntax and functionality between PHP and Perl that could cause issues when combining them?

One key difference between PHP and Perl is their syntax for variable interpolation. In Perl, variables are interpolated directly within double quotes, while in PHP, variables are interpolated within double quotes preceded by a dollar sign. To avoid issues when combining them, make sure to properly format variable interpolation according to the language being used.

// Example of correctly interpolating variables in PHP
$name = "John";
echo "Hello, $name!";