php exec() - mysqldump creates an empty file

Question

I want to create a backup from a database, but I get only a blank file.

include('config.php');

$command = "mysqldump --opt -h ".$_host." -u ".$_user." -p ".$_pass." ".$_db." > test.sql";
exec($command);

echo "<br />".$command;

test.sql is created where the .php file is located.

Edit:

Note! I'm using XAMPP WINDOWS !

Solution:

Because I'm using a Windows Web Server (XAMPP), I needed to specify the path:

$command = 'd:\xampp\mysql\bin\mysqldump --opt -u '.$_user.' -p'.$_pass.' '.$_db.' > test.sql';

I removed the space between the -p and the pass. It looks like: -pMYPASSWORD
Replaced " with '

I think if you are using a Linux based web server, you don't have to specify the path for mysqldump.

Cheers! :-)

I think you should remove the space between the -p and the password. — Denys Séguret
– Denys Séguret, Commented Aug 17, 2012 at 10:46
Have you tried echo-ing out the command (to make sure all the variables are passed as expected) or testing it manually with the right input? — Fluffeh
– Fluffeh, Commented Aug 17, 2012 at 10:51

Roman C · Accepted Answer · 2013-10-04 20:00:33Z

4

Try this one:

$command = 'd:\xampp\mysql\bin\mysqldump --opt -u '.$_user.' -p'.$_pass.' '.$_db.' > test.sql 2>&1';

-its about permission issue.

edited Oct 4, 2013 at 20:00

Roman C

1

answered Oct 4, 2013 at 19:42

javinczki

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1 Comment

Nick Zinger Over a year ago

The 2>&1 at the end helped me at least get an error instead of an empty file.

Jordi Kroon · Accepted Answer · 2015-03-22 13:42:16Z

4

These are the parameters

-uROOT -pPASSWORD --databases DB --result-file=FILE.SQL

edited Mar 22, 2015 at 13:42

answered Aug 17, 2012 at 10:51

Jordi Kroon

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1 Comment

Denys Séguret Over a year ago

for -u, you can have a space.

Ed Heal · Accepted Answer · 2012-08-17 10:58:34Z

0

If you look at the manual for exec the output goes to an array that is the second argument. That may be the source of the problem.

answered Aug 17, 2012 at 10:58

Ed Heal

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Denys Séguret · Accepted Answer · 2012-08-17 10:58:51Z

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You should remove the space between the -p and the password.

--opt isn't needed with recent versions of mysql.

Other than that, your syntax is correct so if it doesn't work with the -p fix, you should check the parameters and the produced command.

edited Aug 17, 2012 at 10:58

answered Aug 17, 2012 at 10:47

Denys Séguret

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Comments

Jacob Goulden · Accepted Answer · 2013-06-12 17:26:57Z

0

Take the variables out of the quotes and remove --opt.

Also make sure that you are having unique file names

$backupfile = $dbname . date("Y-m-d-H-i-s") . '.sql';

$command = "D:\xampp\mysql\bin\mysqldump -u $_user -p$_pass $_db > $backupfile";

system($command);

answered Jun 12, 2013 at 17:26

Jacob Goulden

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yulolimum · Accepted Answer · 2014-01-25 07:38:23Z

0

For those on Macs

I was battling this issue the entire evening today. Silly mistake: one needs to chmod the directory that you are dumping the file to.

I ran this which fixed the issue:

chmod -R 777 your_dump_directory/

answered Jan 25, 2014 at 7:38

yulolimum

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Comments

Roberth Moreira · Accepted Answer · 2016-05-26 09:52:19Z

Try this:

$DBUSER="user";
$DBPASSWD="password";
$DATABASE="DBname";

$filename = "backup-" . date("d-m-Y") . ".sql";

$command = '"C:\Program Files\MySQL\MySQL Server 5.5\bin\mysqldump.exe" '.$DATABASE ." -u".$DBUSER ." -p".$DBPASSWD." > your_web_site/$filename";
passthru($command);

Change the route to the direction of the mysqldump.exe application of your computer.
Respect the " " inside the command.

Then force the download of the file:

if (file_exists("your_web_site/".$filename)) {
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="'.basename($filename).'"');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
readfile("your_web_site/".$filename);
exit;
}

Edit: You have to give permissions to the folder where you keep copies.

Vincent Cheung · Accepted Answer · 2022-10-20 02:52:14Z

0

Please make sure set PATH for MySQL bin folder for WAMP.

answered Oct 20, 2022 at 2:52

Vincent Cheung

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