First of all, I would like to point out that this is NOT a duplicate to this or this and other related questions. I am asking how to get the output as well and my question is mostly related to that.
I need to run a bash script from PHP and get its output in PHP. However, doing:
shell_exec('<myscript> > /dev/null 2>/dev/null &');
top -c | grep <myscript>
Solution for a similar problem: A few years ago I had a similar problem. I had to upload a file to a FTP server. I wondered how to communicate to the FTP server that the file was uploaded completely, so that the FTP server can perform some tasks on it. My solution was to rename the file to something like *.completed after it was uploaded completely. Then the process on the FTP server could look for *.completed files only.
Solution adjusted to your problem: I'd suggest you to rename your temp file after it was generated by your bash script. This way you can independently find out if the script was executed successfully.
shell_exec() could look like this:
shell_exec('<myscript> > tmp-file && mv tmp-file tmp-file.completed &');
Be aware that this only redirects the channel STDOUT into the the tmp-file. If you also want to redirect STDERR into the tmp-file, try this:
shell_exec('<myscript> &> tmp-file && mv tmp-file tmp-file.completed &');