I am running the following code to run bash commands
shell_exec("sudo sh script.sh $conf_file");
The $config_file holds the value of e.g abc.conf
In my script.sh file
#!/bin/bash
mv $1 /etc/apache2/sites-available/
I have also given permission to www-data user to use sudo without password by going to sudo visudo and added the following line in last
www-data ALL=NOPASSWD: /var/www/html/myapp/script.sh
You are running sh by sudo, not /var/www/html/myapp/script.sh one. It's also strange why you are runing script.sh by sh when your script begins with line #!/bin/bash. Simply try to change shell_exec to:
shell_exec("sudo /var/www/html/myapp/script.sh $conf_file");