I'm trying to execute a linux command in PHP, here is my sample code:
$command = "last -F";
$o = shell_exec($command);
print_r($o);
Most of the Linux commands gives me an output, but for the Last -F command, I have no output. Why is it so?
Try This Explaination. Your issue MAY be that the last line of last -F is a new-line. shell_exec() only returns the last line of the command, and therefore, if that line is empty, you get nothing, nada.
As an alternative, try exec(), this will allow you to capture the return value (success or failure of execution) as well as the entirety of the command's output. Check it out here
You are executing that command as web user (nobody or www-data), which is a limited privileged user.You have to execute that command as root. Unfortunately giving sudo permission or full permission to web user is really a bad idea. So I recommend make a cron or background script that execute last -F and write output to a file. You can read that file from your PHP script.
You can make a script runs in background like this.
#!/bin/bash
while [ true ]; do
last -F > /tmp/myfile
done
save the code as mycron.sh
chmod +x mycron.sh
mycron.sh &
Read the file /tmp/myfile from your PHP Program. It will give the exact output of that command.
Related
I'm trying to run a Python script from PHP using the following command:
exec('/usr/bin/python2.7 /srv/http/assets/py/switch.py arg1 arg2');
However, PHP simply doesn't produce any output. Error reporting is set to E_ALL and display_errors is on.
Here's what I've tried:
I used python2, /usr/bin/python2 and python2.7 instead of /usr/bin/python2.7
I also used a relative path instead of an absolute path which didn't change anything either.
I tried using the commands exec, shell_exec, system.
However, if I run
if (exec('echo TEST') == 'TEST')
{
echo 'exec works!';
}
it works perfectly fine while shutdown now doesn't do anything.
PHP has the permissions to access and execute the file.
EDIT: Thanks to Alejandro, I was able to fix the problem. If you have the same problem, don't forget that your webserver probably/hopefully doesn't run as root. Try logging in as your webserver's user or a user with similar permissions and try to run the commands yourself.
Tested on Ubuntu Server 10.04. I hope it helps you also on Arch Linux.
In PHP use shell_exec function:
Execute command via shell and return the complete output as a string.
It returns the output from the executed command or NULL if an error
occurred or the command produces no output.
<?php
$command = escapeshellcmd('/usr/custom/test.py');
$output = shell_exec($command);
echo $output;
?>
Into Python file test.py, verify this text in first line: (see shebang explain):
#!/usr/bin/env python
If you have several versions of Python installed, /usr/bin/env will
ensure the interpreter used is the first one on your environment's
$PATH. The alternative would be to hardcode something like
#!/usr/bin/python; that's ok, but less flexible.
In Unix, an executable file that's meant to be interpreted can indicate
what interpreter to use by having a #! at the start of the first line,
followed by the interpreter (and any flags it may need).
If you're talking about other platforms, of course, this rule does not
apply (but that "shebang line" does no harm, and will help if you ever
copy that script to a platform with a Unix base, such as Linux,
Mac, etc).
This applies when you run it in Unix by making it executable
(chmod +x myscript.py) and then running it directly: ./myscript.py,
rather than just python myscript.py
To make executable a file on unix-type platforms:
chmod +x myscript.py
Also Python file must have correct privileges (execution for user www-data / apache if PHP script runs in browser or curl)
and/or must be "executable". Also all commands into .py file must have correct privileges.
Taken from php manual:
Just a quick reminder for those trying to use shell_exec on a
unix-type platform and can't seem to get it to work. PHP executes as
the web user on the system (generally www for Apache), so you need to
make sure that the web user has rights to whatever files or
directories that you are trying to use in the shell_exec command.
Other wise, it won't appear to be doing anything.
I recommend using passthru and handling the output buffer directly:
ob_start();
passthru('/usr/bin/python2.7 /srv/http/assets/py/switch.py arg1 arg2');
$output = ob_get_clean();
If you want to know the return status of the command and get the entire stdout output you can actually use exec:
$command = 'ls';
exec($command, $out, $status);
$out is an array of all lines. $status is the return status. Very useful for debugging.
If you also want to see the stderr output you can either play with proc_open or simply add 2>&1 to your $command. The latter is often sufficient to get things working and way faster to "implement".
To clarify which command to use based on the situation
exec() - Execute an external program
system() - Execute an external program and display the output
passthru() - Execute an external program and display raw output
Source: http://php.net/manual/en/function.exec.php
Alejandro nailed it, adding clarification to the exception (Ubuntu or Debian) - I don't have the rep to add to the answer itself:
sudoers file:
sudo visudo
exception added:
www-data ALL=(ALL) NOPASSWD: ALL
In my case I needed to create a new folder in the www directory called scripts. Within scripts I added a new file called test.py.
I then used sudo chown www-data:root scripts and sudo chown www-data:root test.py.
Then I went to the new scripts directory and used sudo chmod +x test.py.
My test.py file it looks like this. Note the different Python version:
#!/usr/bin/env python3.5
print("Hello World!")
From php I now do this:
$message = exec("/var/www/scripts/test.py 2>&1");
print_r($message);
And you should see: Hello World!
The above methods seem to be complex. Use my method as a reference.
I have these two files:
run.php
mkdir.py
Here, I've created an HTML page which contains a GO button. Whenever you press this button a new folder will be created in directory whose path you have mentioned.
run.php
<html>
<body>
<head>
<title>
run
</title>
</head>
<form method="post">
<input type="submit" value="GO" name="GO">
</form>
</body>
</html>
<?php
if(isset($_POST['GO']))
{
shell_exec("python /var/www/html/lab/mkdir.py");
echo"success";
}
?>
mkdir.py
#!/usr/bin/env python
import os
os.makedirs("thisfolder");
This is so trivial, but just wanted to help anyone who already followed along Alejandro's suggestion but encountered this error:
sh: blabla.py: command not found
If anyone encountered that error, then a little change needs to be made to the php file by Alejandro:
$command = escapeshellcmd('python blabla.py');
All the options above create new system process. Which is a performance nightmare.
For this purpose I stitched together PHP module with "transparent" calls to Python.
https://github.com/kirmorozov/runpy
It may be tricky to compile, but will save system processes and will let you keep Python runtime between PHP calls.
Inspired by Alejandro Quiroz:
<?php
$command = escapeshellcmd('python test.py');
$output = shell_exec($command);
echo $output;
?>
Need to add Python, and don't need the path.
Good day all, I m trying to implement a web interface that will operate my wireless network.
One of the operations is to configure my card into monitor mode. pretty simple, if you run this command:
bash prepareCard.sh wlan0
and the script prepareCard.sh is as follows:
#! /bin/bash
IFACE=$1
ifconfig $IFACE down
iwconfig $IFACE mode monitor
ifconfig $IFACE up
Now I want to execute this script via a php script:
$cmd = shell_exec("bash prepareCard.sh wlan0");
when I check if the card has been set to monitor mode, nothing! it's still in management mode!!
Can you please tell me where did I go wrong?
Assuming the webserver user that is running the script does not have sufficient permissions, you can try this way to fix it:
Use command visudo to edit /etc/sudoers and add this line:
ALL ALL=(root) NOPASSWD: /absolute/path/prepareCard.sh
Make sure to set permissions 700 to the script, so no one else can edit it. Then execute your script with sudo like this:
$cmd = shell_exec("sudo /absolute/path/prepareCard.sh wlan0");
That should execute the script as root without a need to enter a password.
One good way to debug BASH scripts is to set debug mode on (either by passing an -x flag to bash in your shell_exec call, by running set -x, or in the shebang line #!/bin/bash -x). This shows you what's going on during execution of the bash script. In your case, I suggest the first case, since you don't know if the script is even being loaded in the first place.
$cmd = shell_exec("bash -x prepareCard.sh wlan0");
After that, you should have more in your $cmd variable.
purpose: use php to input commands directly into the minecraft server console
Im trying to use a php script (run from browser) to exec() a shell script. when i run the php from a terminal it works! But in the browser, nothing happens.
exec('sudo -u root sh /home/minecraft/whitelist-reload.sh', $out, $ret_val);
When running from terminal, i get a "array 0" but the browser gives me a "array 1"
what is the issue?
and once i run the shell, shouldn't everything after that work as if you were on a terminal?(does it matter what is inside of shell script?)
the shell has all rx permissions and is in the sudoers file as
www-data ALL = NOPASSWD: /home/minecraft/whitelist-reload.sh
The problem is, that you run the script on a terminal as a user that probably has the sudo rights, whereas the apache/webserver user doesn't, so the $ret_val (which is actually just a status code) is set to 1 (means error).
try var_dump($out); in both cases to see the results of your exec call. To do this kind of thing from the browser, you might want to look into proc_open and family, or have a script that is chmod'ed to 777, so the apache user can run it, too. Let that script then call the actual shell script and return it's output back. This is, however very dangerous, and should only be used for testing environments on your own machine. Never do this in production environments!
I have posted a couple of questions here, too that might prove informative:
interaction over ssh
opening a second shell, and load profile variables AND call another script
Turns out... after inputting www-data into the sudoers file, all i needed to do was take of the "-u root" after it
I have to design a interface using PHP for a software written in python. Currently this software is used from command line by passing input, mostly the input is a text file. There are series of steps and for every step a python script is called. Every step takes a text file as input and an generates an output text file in the folder decided by the user. I am using system() of php but I can't see the output but when I use the same command from command line it generates the output. Example of command :
python /software/qiime-1.4.0-release/bin/check_id_map.py -m /home/qiime/sample/Fasting_Map.txt -o /home/qiime/sample/mapping_output -v
try this
$script = 'software/qiime-1.4.0-release/bin/check_id_map.py -m /home/qiime/sample/Fasting_Map.txt -o /home/qiime/sample/mapping_output -v';
$a = exec($script);
If you are not on windows, have you tried adding 2>&1 (redirect stderr to stdout) to the end of the command?
$output = system("python /software/qiime-1.4.0-release/bin/check_id_map.py -m /home/qiime/sample/Fasting_Map.txt -o /home/qiime/sample/mapping_output -v 2>&1", $exitcode);
Found from http://www.php.net/manual/en/function.system.php#108713
Also the doc says that it
Returns the last line of the command output on success, and FALSE on
failure.
So if you are trying to get multiple lines, you may need to redirect it to a file and read that in.
instead of system() try surrounding the code in `ticks`...
It has a similar functionality but behaves a little differently in the way it returns the output..
I'm writing a class who let me access to recutils through PHP.
I have a 'database' file called books.rec in ../database/ and a script who runs my Recutils.php class.
My class simply launch system application with correct parameters.
But When I try to use recins with PHP's exec function, the command doesn't work will it work in command line.
This is the command that is executed by my script :
recins -f Title -v "Moi" -f Author -v "Moche" -f Location -v "loaned" -t Books ../database/books.rec
With PHP : Nothing, the record is not inserted (no error message at all too).
In terminal : OK, the command is well done and my record is inserted.
I also have a method to do a select operation using recsel and it works very well, will it use exactly the same file (and runs from exec too).
So, could someone explain me why the command don't work will another with the same file work ?
Thanks
PS : Further informations : http://www.gnu.org/software/recutils/
I would double check that you are running the command as the same user from the command line and your php script. That may be the problem. exec('whoami')
You said you had a script that starts your php script it should be the same user as that.
You might also want to running a simpler exec command to see if that will work first.
Other things to try:
Try checking stderr output exec('ls /tmp 2>&1', $out); This will redirect standard error to standard out so you get both.
Try using php's shell_exec() which will invoke a shell just like when you are running from the command line(eg. bash). shell_exec('ls /tmp 2>&1 >> /tmp/log') should even put all output into a log file.
I don't think this will help you but it is something to try if all else fails, set it as a background process and see if it completes. exec('nohup php process.php > process.out 2> process.err < /dev/null &'). The & will set the command to run in the background and let the script continue.
Good Luck
Is recins command accessible for PHP ? Also is path to books.rec correct ?
Try with absolute path.