I have created generic text files, scripts, etc. in order to perform quick installs of the software to various subdirectories.

I inserted variables (e.g. account number) in specific locations within each file, and upon running the install script, I want the 'values' of these variables inserted. But, what is happening is that the raw variables are printed without interpretation.

Here is a sample of the code:
~~~~~~~~~~~~~~~~~~~~~~

sub newfile_create {
$account_number = "12345";

$master_file = "/usr/local/foo/htdocs/master_file.txt";
open (IN, "$master_file") or die "Couldn't open file: $!"; 
$new_file_content = join("", <IN>);
close (IN);

# Note -- the 'master file' contains a variable, $account_number that 
+needs to be substituted when the file contents are written into the v
+ariable, $new_file_content before writing this data into the $new_fil
+e_path location (file).

$new_file_path = "/usr/local/foo/htdocs/sub/file1.js";

open(IN, ">$new_file_path");
print IN "$new_file_content";
close(IN);

return;
}
[download]

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How can I get the $account_number var interpreted before writing to the new file?

Thank you.