PHP Exec executes some commands, but not others

Posted by davecoventry on June 13, 2010 at 11:36am

I'm trying to get the difference between 2 files on my Debian system.

<?php
$output=`diff path/to/file1 path/to/file2`;
echo "<hr>".$output."<hr>";
?>

Gives a page with "<hr><hr>".

However, this:

<?php
$output=`ls -la path/to/files/`;
echo "<hr>".$output."<hr>";
?>

Gives me a listing of the directory as expected.

Do the executables need to be registered somewhere?

Comments

Posted by criznach on June 13, 2010 at 4:57pm

Does your apache user have the necessary permissions to access the files and to execute the diff command?

Posted by davecoventry on June 14, 2010 at 9:17pm

Odd.

<?php
$output=`diff path/to/file1 path/to/file2>/tmp/difffile`;
echo "<hr>".$output."<hr>";
?>

Produces the file /tmp/diffile with the 'diff' output.

But I would have expected the following:

<?php
$output=`diff path/to/file1 path/to/file2`;
echo "<hr>".$output."<hr>";
?>

to produce the contents of the diff file as the $output.