this is my code:
var vlc = spawn("cvlc", [file], {uid:1000,gid:1000});
The program in node is executed through an instance of forever launched by root user. As cvlc does not permit to be executed as root I need it to be executed as normal user.
This is the way node.js explains how to do it: http://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options but does not work.
Maybe try
var vlc = spawn("su -c cvlc -s /bin/sh otheruser"....)
The command string is just a string, I have no idea if the spawn function will try to parse it or not, or straight up fail. I'm just trying to give you something to try, so give it a shot.
Related
let cp = require("child_process");
console.log("Opening Chrome");
cp.execSync("start chrome");
console.log("Chrome Opened");
I have opened the chome using above command but don't know how to close this using similar one.
If anyone of you know let me know!!
Well here in your program you are relying on some platform command-line tools, so you could try to achieve the same result with a similar platform-specific tool.
For example, there is kill -9 PID command that can kill any process, but you need to know the PID of your process.
I would advice you to use spawn command instead of execSync if you just want to spawn some program and have more controll over it.
I would like to run a batch of bash commands (all together) in a server shell through a python3 script in my local machine.
The reason why I'm not running the python3 script on my laptop is that I can't create the same environment on the server and I want to keep the settings I have on my machine while executing the script.
What I would like to do is:
-Run python commands locally
-Run at a certain point those command on the server
-Wait for the end of server execution
-Continue running python script
(This will be done in a loop)
What I'm trying is to put all the commands in a bash script ssh_commands.sh and use the following command:
subprocess.call('cat ssh_commands.sh | ssh -T -S {} -p {} {}'.format(socket, port, user_host).split(),shell=True)
But when the execution of the script reaches that line get stuck until subprocess.call timeout. The execution of the script anyway won't take that much. The only way to stop the script before is through Ctrl+C
I've also tried to set up the ssh connection in the ~/.ssh/config file but I'm getting the same result.
I know that ssh connection works fine and if I run ssh_commands.sh on the server manually, it runs without any problem.
Can somebody suggest:
- A way for fixing what I'm trying to do
- A better way for achieving the final result written above
- Some debugging way to find out what could be the problem
Thank you in advance
To expand on my comment - and I haven't tested your specific case with ssh, could be there are other complications there). This is actually copy/pasted from my own code in a situation that I already know works.
from subprocess import Popen, PIPE, DEVNULL
from shlex import split as sh_split
proc1 = Popen(sh_split(file_cmd1), stdout=PIPE)
proc2 = Popen(file_cmd2, shell=True, stdin=proc1.stdout, stdout=PIPE)
proc1.stdout.close()
I have a specific reason to use shell=True in the second, but you should probably be able to use shlex.split there too I'm guessing.
Basically you're running one command, outputting to `PIPE´, then using this as input for the second command.
I am creating a command line program to act as a shortcut for my environment. Commands like $ cd $enterprise/products/<product> are so common, that I like to compile into: $ enterprise product.
My problem is: I cannot change shell directory directly, like running $ cd $enterprise/products/<product> with process.chdir.
Using console.log(process.cwd()) shows that the directory has changed, but not on shell, only on nodejs internal process(I think it's running on a own shell).
Typing $ pwd in shell shows that I still are on the same folder.
I was searching for a solution, like a shell script that interprets the output of a nodejs file, then source the output.
Thanks.
This is actually bit trickier than it sounds.
You can't just change the working directory of the shell that is running the process, without making assumptions about which shell it is or the OS (I personally use applescript to spawn new terminal tabs).
What we can do, however, is spawn a new shell!
let child_process = require('child_process');
child_process.spawn(
// With this variable we know we use the same shell as the one that started this process
process.env.SHELL,
{
// Change the cwd
cwd: `${process.cwd()}/products/${product_id}`,
// This makes this process "take over" the terminal
stdio: 'inherit',
// If you want, you can also add more environment variables here, but you can also remove this line
env: { ...process.env, extra_environment: 'some value' },
},
);
When you run this, it seems like you cd into a directory, but actually you are still running inside nodejs!
You can't do this; every child process has its own working directory inherited from the parent. In this case, your cd gets its working directory from its parent (your shell). A child process can't change the directory – or any other state – of the parent process.
I'have a process created with a spawn in nodejs with the option shell:true so the process starts in a real shell. So when I try to kill this process with streamingTask.kill() it's not working. Without the option shell:true everything works fine.
This is how my code looks:
var options = {shell:true};
streamingTask = spawn('gst-launch-1.0',args,options);
...
streamingTask.kill()
So how can I kill this process now?
This doesn't work because you are killing the shell process itself, not the child process(es) spawned by the shell (gst-launch-1.0 in your case).
There's a package on npm called tree-kill that provides an easy one-line solution:
var kill = require('tree-kill');
kill(streamingTask.pid);
I've my program in bash and I want to launch a node program to get the string that it return, like in this way:
#!/bin/bash
mystring=$( node getString.js)
mplayer $mystring
Googling I found that I should inlcude
#!/usr/bin/env node
But I need to use string to give it to mplayer.. any ideas?
Solution
As Zac suggesting (and thanks to this link) I solved my problem in this way:
script.sh
#!/bin/bash
mplayer ${1}
script.js
/* do whatever you need */
var output="string"
var sys = require('sys');
var exec = require('child_process').exec;
function puts(error, stdout, stderr) { sys.puts(stdout); }
exec("./script.sh " + output, puts);
Consider simply writing an executable Node script (with the #!/bin/env node line), and, instead of using Bash, just use Node to run the external UNIX command. You can use the child_process module for this, as illustrated in this example. This question is also helpful when debugging shell-style subcommands in Node scripts.
If your example really is all you need to do in Bash, this should be sufficient. The #!/bin/env node line allows your script, once marked as executable, to run as its own program, without having to be invoked with node.