php Post txt file content to textarea on another page - php

Question

I am writing an app to delete and modify files in a directory. I deleted files successfully. And now I want to modify and update content to the same file using textarea on another page.
<form enctype="multipart/form-data" method="post">
<div class="span7">
<table>
<thead>
<tr>
<th> List of files </th>
<tr>
</thead>
<?php
$files = glob("UploadFile/"."*");
foreach($files as $txt)
{
if(mime_content_type($txt)=="text/plain")
{
$txtname = basename($txt);
echo "<tr><td><input type='radio' name='txt' value='$txtname'/> ".$txtname."</td></tr>";
}
}
?>
</table>
</div>
<div class="span8">
<button type="submit" name="submit" value="Edit">Edit</button>
<button type="submit" name="submit" value="Delete">Delete</button>
</div>
<?php
global $txtname;
$val = $_POST["submit"];
$txtname = $_POST["txt"];
if($val=="Delete")
unlink("UploadFile/".$txtname);
else if($val=="Edit")
{
$content=file_get_contents("UploadFile/".$txtname);
header('Location:/edit.php');
/* send content to this 'edit.php' page */
}
?>
</form>
And the edit.php page, i simply checked if the code is working. It works fine.
<?php
if($_POST['append'])
{
$file_open = fopen("UploadFile/file.txt","a+");
fwrite($file_open, $_POST['append']);
fclose($file_open);
}
?>
<form enctype="multipart/form-data" action="<?=$PHP_SELF?>" method="post">
<textarea name="append" value="">
<?php
echo $content;
$datalines = file ("UploadFile/file.txt");
foreach ($datalines as $zz)
{
echo $zz;
}
?>
</textarea>
<button type="submit" name="submit" value="save"> Save </button>
How do I get the contents of the file to textarea for modifying it.Update: I want to save changes to the same file. Thank you

Answer 1

<?php
if(isset($_POST['text']))
{
file_put_contents("file.txt",$_POST['text']);
header("Location: ".$_SERVER['PHP_SELF']);
exit;
}
$text = file_get_contents("file.txt");
?>
<form method="post">
<textarea name="text"><?=$text?></textarea>
<input type="submit">
</form>
with listing
if(isset($_POST['text']))
{
file_put_contents("UploadFile/".basename($_POST['file']),$_POST['text']);
header("Location: ".$_SERVER['PHP_SELF']);
exit;
}
if(isset($_GET['file']))
{
$text = file_get_contents("UploadFile/".basename($_GET['file']));
?>
<form method="post">
<input type="hidden" name="file" value="<?=urlencode($_GET['file'])?>">
<textarea name="text"><?=$text?></textarea>
<input type="submit">
</form>
<?
} else {
$files = glob("UploadFile/*");
foreach ($files as $f)
{
$f=basename($f);
?><?=htmlspecialchars($f)?><br><?
}
}