Linux Shell & placed behind the startup parameters to set this process as a background process

& placed after the startup parameter to set this process as a background process

By default, the process is the foreground process, then the shell is occupied, we can not do other operations, for those who do not interact with the process, many times, we want to start in the background, you can start the parameters with a ' & ' to achieve this purpose.

Such as:

Tianfang > Run &
[1] 11319
Tianfang >

When the process switches to the background, we call it job. Switching to the background will output the relevant job information, with the previous output as [1] 11319 cases: [1] indicates that the job ID is 1,11319 indicates that the process ID is 11319. A process that switches to the background can still be viewed with the PS command

In Linux, the essential difference between a command and A & without &

Plus & is handing the command to the Linux kernel to run a process task,

Do not start a process task through the shell.

Linux is a multitasking operating system, and theshell can be understood as a single-tasking operating system (like dos).

Single-tasking operating system, you can start another task by yourself.

Multitasking operating system, you can run multiple tasks at the same time.

Linux Shell & placed behind the startup parameters to set this process as a background process