TWO linux commands executed in background called by PHP exec() function - php

Question

I try to execute two linux commands in background by single php exec() call.
My first command makes some files backup:
cp -r ../source ../destination
Second command creates a file "DONE.txt" when backup is complete:
touch ../destination/DONE.txt
Moreover I base on php manual and use following background exec() call:
exec('bash -c "exec nohup setsid '.$twoCommands.' > /dev/null 2>&1 &"');
The whole code is bellow:
exec('bash -c "exec nohup setsid { cp -r ../source ../destination && touch ../destination/DONE.txt; } > /dev/null 2>&1 &"');
And... it doesn't work:) But why?
If I use only one command:
exec('bash -c "exec nohup setsid cp -r ../source ../destination > /dev/null 2>&1 &"');
It works well:)

Answer 1

I have no idea why you're trying to make this so complicated. nohup and setsid are two completely separate functions, not arguments you pass to exec. Nor do you even need to call exec in the command itself; that's the point of using exec in PHP. Output redirection is only necessary if you need the PHP script to continue in the background after the exec call rather than waiting for it to finish.
[root#test~]# ll
total 8
drwxr-xr-x. 2 root root 24 Jun 27 13:40 source
[root#test~]# ll source
total 0
-rw-r--r--. 1 root root 0 Jun 27 13:40 1
-rw-r--r--. 1 root root 0 Jun 27 13:40 2
[root#test~]# php -a
Interactive shell
php > exec("cp -r ./source ./destination && touch ./destination/DONE.txt");
php > exit
[root#test~]# ll destination/
total 0
-rw-r--r--. 1 root root 0 Jun 27 13:44 1
-rw-r--r--. 1 root root 0 Jun 27 13:44 2
-rw-r--r--. 1 root root 0 Jun 27 13:44 DONE.txt
[root#test~]#