Why my shell_exec() donot work.
 

Hi.
I am new man to php.I want to execute a shell script using php on a linux,
but I failed.
I found some useful resource in this site,and then tested,but the question has not been soluted.
vj123 met the the same question as me,there is not a clear answer on this page.
http://www.linuxquestions.org/questi...ec#post2114059
slam said he has soluted the similar question,I tried to test on his mehtod
but still didnot success.
http://www.linuxquestions.org/questi...ec#post2114059

I tied the to execute the following code:
<?php
$cmd='/root/hy6.sh' ;
$output = shell_exec($cmd);
echo "<pre>$output</pre>";
?>

-------hy6.sh--------
#!/bin/sh
su - postgres -c "'/usr/local/pgsql/bin/pg_dump' 'helpdesk'> '/tmp/helpdesk/helpdeskback.dump'"

---------
I directly execute it like this : sh /root/hy6.sh
It works,but when I execute it in php,there is not any response.

If I execute like this:
shell_exec("su - postgres -c '/usr/local/pgsql/bin/pg_dump' 'helpdesk' > '/tmp/helpdesk/helpdesk.dump'");
there will be create a new file in the folder(/tmp/helpdesk/),but It has
0 bytes.
If I execute like this:
shell_exec("su - postgres -c \"'/usr/local/pgsql/bin/pg_dump' 'helpdesk' > '/tmp/helpdesk/helpdesk.dump'\"");
It doesnot work.Because I am not good at linux,so I want your help.
Any advice is appreciate,
Suqin

I create a shell like this:
---
#!/bin/sh
echo "hello"
------
then I executed it in php:
echo shell_exec('/tmp/helpdesk/hy10.sh');
It works.but hy6 still does not work,I cannot find the reason.

My guess is that the user that runs php (apache? nobody?) can't
"su - postgres" w/o a password... how do you enable verbose error
messages in PHP? I'm not proficient in PHP, it's been ages that
I last had to use it :}


Cheers,
Tink

Tink,thanks your reply.
I try to execute like this,
shell_exec("su - root -s /tmp/helpdesk/hy6.sh")

In /var/log/message ,I can find that a session has been opened for root ,but then nothing has
happened.

I execute it like this
shell_exec("su - root -s /bin/sh -c '/usr/local/pgsql/bin/pg_dump' 'helpdesk' > '/tmp/helpdesk/helpdesk.dump'" ." 2>&1");

the error is :standard in must be a tty.
My linux`s user is root,password is webcharge.In postgre,I create an user,root,password is a
there is realations between there?

thanks a lot
suqin