Get Original Files

input.txt

4
jfjr959493ajsks999s9_A.txt
sieeke4444abcksl4krk_A.cpp
a8b95b8k4ra9f4ka92kf_A.cs
A.java

orig

<?php
$data = file_get_contents('./input.txt', true);
$files = explode("\n", $data);
foreach ($files as $key => $value) {
	$file_name=explode(".",$value);
	if($file_name[1]!=""){
		$file_name2=explode("_",$value);
		if($file_name2[1]==""){
			echo $file_name2[0]."<br>\n";
		} else {
			echo $file_name2[1]."<br>\n";
		}	
	} 
}
?>

origin_2

<?php
$data = file_get_contents('./input.txt', true);
$files = explode("\n", $data);
foreach ($files as $key => $value) {
  	if (preg_match('/[A-Z](.*)/', $value, $match_patern))
    {
        echo  $match_patern[0]."\n";
    }
}
?>

output

A.txt<br>
A.cpp<br>
A.cs<br>
A.java