I am trying learn to execute shell scripts from within PHP code. So, I made a test program to execute a bash script from within PHP. However, it has no effect. The relevant code is shown below.
<?php
.......
shell_exec('/bin/bash /var/www/html/just_touch.sh');
?>
The just_touch.sh script just creates a new file, like as shown below.
touch /home/user/some.txt
I was expecting to have file /home/user/some.txt after execution, but no, it isn't made. What mistake, am I doing?
P.S: The following code works though.
$output = shell_exec('ls /home/user');
echo $output;
Does this have anything to do with permissions?
Moreover, I notice that while this prints "Can you see me?".
$output = shell_exec('echo Can you see me?');
echo $output;
This doesn't!
shell_exec('echo Can you see me?')
What is going on here?
Stderr is lost when using shell_exec. You might wan't to use:
shell_exec('/bin/bash /var/www/html/just_touch.sh 2>&1');
I have a server running on Linux that execute commands to 12 nodes (12 computers with Linux running in them). I recently downloaded PHP on the server to create web pages that can execute commands by opening a specific PHP file.
I used exec(), passthru(), shell_exec(), and system(). system() is the only one that returns a part of my code. I would like PHP to act like open termainal command in linux and I cannot figure out how to do it!
Here is an example of what is happening now (Linux directly vs PHP):
When using linux open terminal command directly:
user#wizard:/home/hyperwall/Desktop> /usr/local/bin/chbg -mt
I get an output:
The following settings will be used:
option = mtsu COLOR = IMAGE = imagehereyouknow!
NODES = LOCAL
and additional code to send it to 12 nodes.
Now with PHP:
switch($_REQUEST['do'])
{ case 'test':
echo system('/usr/local/bin/chbg -mt');
break;
}
Output:
The following settings will be used:
option = mtsu COLOR = IMAGE = imagehereyouknow!
NODES = LOCAL
And stops! Anyone has an explanation of what is happening? And how to fix it? Only system displays part of the code the other functions display nothing!
My First thought is it can be something about std and output error. Some softwares dump some informations on std out and some in std error. When you are not redirecting std error to std out, most of the system calls only returns the stdout part. It sounds thats why you see the whole output in terminal and can't in the system calls.
So try with
/usr/local/bin/chbg -mt 2>&1
Edit:
Also for a temporary work through, you can try some other things. For example redirect the output to file next to the script and read its contents after executing the command, This way you can use the exec:
exec("usr/local/bin/chbg -mt 2>&1 > chbg_out");
//Then start reading chbg_out and see is it work
Edit2
Also it does not make sense why others not working for you.
For example this piece of code written in c, dumps a string in stderr and there is other in stdout.
#include <stdio.h>
#include<stdlib.h>
int main()
{
fputs("\nerr\nrro\nrrr\n",stderr);
fputs("\nou\nuu\nuttt\n",stdout);
return 0;
}
and this php script, tries to run that via exec:
<?php
exec("/tmp/ctest",&$result);
foreach ( $result as $v )
{
echo $v;
}
#output ouuuuttt
?>
See it still dumps out the stdout. But it did not receive the stderr.
Now consider this:
<?php
exec("/tmp/ctest 2>&1",&$result);
foreach ( $result as $v )
{
echo $v;
}
//output: errrrorrrouuuuttt
?>
See, this time we got the whole outputs.
This time the system:
<?php
echo system("/tmp/ctest 2>&1");
//output: err rro rrr ou uu uttt uttt
?>
and so on ...
Maybe your chbg -mt writes additional code to stderr instead of stdout? Try to execute your script inside php like this:
/usr/local/bin/chbg -mt 2>&1
The other responses are good for generic advice. But in this specific case, it appears you are trying to change your background on your desktop. This requires many special considerations because of 'user context':
First, your web server is probably running as a different user, and therefore would not have permissions to change your desktop.
Second, the program probably requires some environmental variables from your user context. For example, X programs need a DISPLAY variable, ssh-agent needs SSH_AGENT_PID and SSH_AUTH_SOCK, etc. I don't know much about changing backgrounds, but I'm guessing it involves D-Bus, which probably requires things like DBUS_SESSION_BUS_ADDRESS, KONSOLE_DBUS_SERVICE, KONSOLE_DBUS_SESSION, and KONSOLE_DBUS_WINDOW. There may be many others. Note that some of these vars change every time you log in, so you can't hard-code them on the PHP side.
For testing, it might be simpler to start your own webserver right from your user session. (i.e. Don't use the system one, it has to run as you. You will need to run it on an alternate port, like 8080). The web server you start manually will have all the 'context' it needs. I'll mention websocketd because it just came out and looks neat.
For "production", you may need to run a daemon in your user context all the time, and have the web server talk to that daemon to 'get stuff done' inside your user context.
PHP's system only returns the last line of execution:
Return Value: Returns the last line of the command output on success, and FALSE on failure.
You will most likely want to use either exec or passthru. exec has an optional parameter to put the output into an array. You could implode the output and use that to echo it.
switch($_REQUEST['do'])
{ case 'test':
exec('/usr/local/bin/chbg -mt', $output);
echo implode('\n', $output); // Could use <br /> if HTML output is desired
break;
}
I think that the result of execution, can changes between users.
First, try to run your PHP script directly into your terminal php yourScript.php
If it runs as expected, go to your Apache service and update it to run with your own credentials
You are trying to change the backgrounds for currently logged in users... While they are using the desktop. Like while I'm typing this message. I minimize my browser and 'ooh my desktop background is different'. Hopefully this is for something important like it turns red when the reactor or overheating.
Anyway to my answer:
Instead of trying to remotely connect and run items as the individual users. Setup each user to run a bash script (in their own account, in their own shell) on a repeating timer. Say every 10 minutes. Have it select the SAME file.. from a network location
/somenetworkshare/backgrounds/images/current.png
Then you can update ALL nodes (1 to a million) just by changing the image itself in /somenetworkshare/backgrounds/images/current.png
I wrote something a while ago that does just this -- you can run a command interpreter (/bin/sh), send it commands, read back responses, send more commands, etc. It uses proc_open() to open a child process and talk to it.
It's at http://github.com/andrasq/quicklib, Quick/Proc/Process.php
Using it would look something like (easier if you have a flexible autoloader; I wrote one of those too in Quicklib):
include 'lib/Quick/Proc/Exception.php';
include 'lib/Quick/Proc/Exists.php';
include 'lib/Quick/Proc/Process.php';
$proc = new Quick_Proc_Process("/bin/sh");
$proc->putInput("pwd\n");
$lines = $proc->getOutputLines($nlines = 10, $timeoutSec = 0.2);
echo $lines[0];
$proc->putInput("date\n");
$lines = $proc->getOutputLines(1, 0.2);
echo $lines[0];
Outputs
/home/andras/quicklib
Sat Feb 21 01:50:39 EST 2015
The unit of communication between php and the process is newline terminated lines. All commands must be newline terminated, and all responses are retrieved in units of lines. Don't forget the newlines, they're hard to identify afterward.
I am working on a project that uses Terminal A on machine A to output to Terminal B on Machine B, both using linux for now. I didnt see it mentioned, but perhaps you can use redirection, something like this in your webserver:
switch($_REQUEST['do'])
{ case 'test':
#process ID on the target (12345, 12346 etc)
echo system('/usr/local/bin/chbg -mt > /proc/<processID>/fd/1');
#OR
#device file on the target (pts/0,tty0, etc)
echo system('/usr/local/bin/chbg -mt > /dev/<TTY-TYPE>/<TTYNUM>');
break;
}
Definitely the permissions need to be set correctly for this to work. The command "mesg y" in a terminal may also assist...Hope that helps.
I'm looking to run a program, and for every output line it generates, execute a PHP script and pass the line content to it.
I know, pretty hard to understand. Here's an example:
Execute script -> script outputs 'Initializing script on 127.0.0.1'. Now it needs to execute a command like php5 input.php 'Initializing script on 127.0.0.1'.
Is this doable? If so, how would I go about doing this?
Edit: to clarify; I basically want command > log.txt but in stead of writing the output to that file, writing it to a PHP script as an argument
PHP is an interpreter much like Bash, Python, etc, so you can do "normal" scripting with it. For example:
#!/usr/bin/php5
<?php
echo "Hello, world!\n";
while($line = fgets(STDIN)) {
echo "> " . $line;
}
?>
Mark the file as executable, then run:
$ /program/that/generates/lines | /path/to/your/php/script
However, contrary to your original question, it sounds to me like you actually want to use JavaScript and possibly AJAX for web purposes. Sane web applications will have the said script run in the background and safely write the results to a file or stream, using AJAX to read it and update the information on the current page.
I'm debugging a PHP script that runs a couple SQL queries and emails a set of users. I'm sure this is a very basic thing, but every time I try to echo, print, or print_r it doesn't appear while running the script.
So say I have this in the script:
print("This should print");
echo "on the command line";
When I run the script via command line php script.php it doesn't actually print anything to the command line while running the script.
Is there a way of having PHP print to console? I feel like I'm missing something extremely basic here.
Thats the method of doing it.
Things to check for are output buffering
http://php.net/manual/en/function.ob-flush.php
Is that code actually being run ? Make sure it doesnt branch before it gets there
A good approach could be:
function log($message)
{
$message = date("H:i:s") . " - $message - ".PHP_EOL;
print($message);
flush();
ob_flush();
}
It will output to your terminal each line you call. Just use :
log("Something");
log("Another line");
The following code working fine for me.
<?php
print("This should print");
echo "on the command line";
?>
with tags.
I know it is old, but I am going post my own solution to this just in case if someone would run into similar situation. I had a problem that a legacy command line PHP script wouldn't print or echo anything to the terminal when DSN is incorrectly configured and the script got stuck for very long time (not sure how long, never waited for it to terminate by itself). After putting ob_end_flush() in the entry line of the script, the output came back to the terminal. So it turned out that all output was buffered and since the script stuck at some point, the output stayed buffered and so never went to the terminal.
how do you issue commands to the shell and then forget it's output and such? for example:
<?php
echo `sleep 2;echo hi`;
echo "foo";
?>
the result for this is hifoo. i would want a result that gives me foohi. why? i want the command issued to the shell simply issued and forgotten, i am confused about why PHP will wait for the result. is such a result possible?
(the idea behind this is setting up the correct number of selenium grid RC instances programatically. currently, it will stop after the first process is opened)
From php.net exec()
If a program is started with this
function, in order for it to continue
running in the background, the output
of the program must be redirected to a
file or another output stream. Failing
to do so will cause PHP to hang until
the execution of the program ends.
The same applies for all shell commands.
It's like anything you do at the command prompt, unless you take measures to put the new command in the background, the shell (and PHP ) will block until the command exits. Try this:
<?php
echo `(sleep 2; echo hi) &`;
echo 'foo';
?>
Note the brackets around your command, without that, the & woulud apply only to the echo , and you'd still have the 2 second pause.