shell_exec returns all of the output stream as a string. exec returns the last line of the output by default, but can provide all output as an array specifed as the second parameter.
See
- http://php.net/manual/en/function.shell-exec.php
- http://php.net/manual/en/function.exec.php
shell_exec returns all of the output stream as a string. exec returns the last line of the output by default, but can provide all output as an array specifed as the second parameter.
See
- http://php.net/manual/en/function.shell-exec.php
- http://php.net/manual/en/function.exec.php
Here are the differences. Note the newlines at the end.
Copy> shell_exec('date')
string(29) "Wed Mar 6 14:18:08 PST 2013\n"
> exec('date')
string(28) "Wed Mar 6 14:18:12 PST 2013"
> shell_exec('whoami')
string(9) "mark\n"
> exec('whoami')
string(8) "mark"
> shell_exec('ifconfig')
string(1244) "eth0 Link encap:Ethernet HWaddr 10:bf:44:44:22:33 \n inet addr:192.168.0.90 Bcast:192.168.0.255 Mask:255.255.255.0\n inet6 addr: fe80::12bf:ffff:eeee:2222/64 Scope:Link\n UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1\n RX packets:16264200 errors:0 dropped:1 overruns:0 frame:0\n TX packets:7205647 errors:0 dropped:0 overruns:0 carrier:0\n collisions:0 txqueuelen:1000 \n RX bytes:13151177627 (13.1 GB) TX bytes:2779457335 (2.7 GB)\n"...
> exec('ifconfig')
string(0) ""
Note that use of the backtick operator is identical to shell_exec().
Update: I really should explain that last one. Looking at this answer years later even I don't know why that came out blank! Daniel explains it above -- it's because exec only returns the last line, and ifconfig's last line happens to be blank.
Videos
On the php manual for shell_exec, it shows that the function returns the output as a string. If you expect output from the program you launch, you need to capture this like so:
$execQuery = "echo -n test_command";
$output = shell_exec($execQuery);
echo $output;
Your question doesn't show trying to capture any data. If you also make sure to connect stdout and stderr when you run your command, you should get a better idea is what is going on. To use your example:
$output = shell_exec("/usr/bin/oneuser create test10 test10 2>&1");
var_dump($output);
That should help you see what is going on. As Shadur suggests, it seems likely that these programs expect an interactive terminal that can enter passwords in order to run. Even if don't need input, they might expect interactive shells. And he's right that su doesn't play nice in this context. There is, however, a correct tool for the job.
You can setup sudo to such that your http user can execute your program as username without a password but NOT be able to do anything else by running visudo or whatever you use to edit your sudoers file and adding this line:
http ALL=(username) /usr/bin/oneadmin
Then in php your command would look something like this:
$execQuery = "sudo -u username /usr/bin/oneadmin postgres -c '/usr/bin/oneuser create test10 test10'";
$out = shell_exec ("$execQuery 2>&1");
echo $out
Try passthru($cmd);
It will allow user's I/O on the Terminal screen.
It does not matter which php function you use to start the script - what lacks is the authorization of your user account.
Either use sudo (preconfigure the web server user to run the exact command without password via visudo, and prefix the command with sudo) or set up a setuid script that executes the command on itself.
What you really need to do is set your web server to run as a specific user (other than 'nobody' for example), or give that user permissions to what you want to execute.
See also: PHP shell_exec() and sudo: must be setuid root