How to concatenate string variables in Bash

Question

In PHP, strings are concatenated together as follows:

$foo = \"Hello\";
$foo .= \" World\";

Here, $foo becomes \"Hello World\"

Answer 1

If you want to append something like an underscore, use escape (\)

FILEPATH=/opt/myfile

This does not work:

echo $FILEPATH_$DATEX

This works fine:

echo $FILEPATH\\_$DATEX