system is just like the C version of the function in that it executes the given command and outputs the result.
The system call also tries to automatically flush the web server's output buffer after each line of output if PHP is running as a server module.
If you need to execute a command and have all the data from the command passed directly back without any interference, use the passthru function.
The command that will be executed.
If the result_code argument is present, then the return status of the executed command will be written to this variable.
Returns the last line of the command output on success, and false on failure.
When allowing user-supplied data to be passed to this function, use escapeshellarg or escapeshellcmd to ensure that users cannot trick the system into executing arbitrary commands.
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.