How set command in background,close terminal and get it back to fg?

bash process

12,180

Solution 1

It's impossible in the way you want.

Let's review some basic concepts:

A process group is a collection of related processes which can all be signalled at once.
A session is a collection of process groups, which are either attached to a single terminal device (known as the controlling terminal) or not attached to any terminal.

If you closed the terminal, all the processes in the session are dead except those (daemons) reparented to the init process. And there's no way to give them a controlling terminal again.

In a word, process reparenting is highly restricted in POSIX systems (daemonizing is an exception) and your requirements can't be satisfied.

Solution 2

Install screen:
```
sudo apt-get install screen
```
Start screen:
```
screen -S session_name
```
Execute your commands what you need.
Detach screen from the terminal (your commands will be still running):

Press CTRL+a+d
Close the terminal
Open another terminal and reattach the last screen session:
```
screen -r
```

For more information and extra options for screen look in man screen.

Solution 3

Have you tried: byobu or tmux which are terminal multiplexers. Not exactly what you are looking for, but it has similar behavior.

byobu-screen

Then run your command, to detach:

byobu-screen -d

To resume:

byobu-screen -r

See https://help.ubuntu.com/community/Screen

12,180

Timur Fayzrakhmanov

Updated on September 18, 2022

Comments

Timur Fayzrakhmanov over 1 year
I'm trying to find out how to run a command in the background and then bring it to the foreground later. I'm fed up of tutorials and answers where people state that it's simple, just append & to the end of the command to get it run in the background. It's working only within a single terminal window. I want to put the command into the background in one terminal and get it back to foreground after reopening the terminal

Example:
```
$ grunt &
$ jobs
$ [1]+  Running  grunt &
```
Of course after closing terminal no one job is found.

Next example:
```
$ grunt & disown #the same behavior has: $ setsid grunt &
$ jobs
$ [nothing] #but ps shows that grunt is working

after close terminal, grunt doesn't work
```
What did I do wrong? Could anybody explain me how to run the command in the background and get it back to foreground.
falconer over 10 years

Those ones also, +1.
Programster over 10 years

Screen or byobu (especially if you are running ubuntu). Byobu is based on screen if I'm correct, but I find that it has extra functionality that I find useful and easier to use, but that's a matter of opinion.
Timur Fayzrakhmanov over 10 years

Thank you good suggestion! Maybe It will be need in the feature!) From Russia with love <3
Programster over 10 years

Technically this is the correct answer, but I believe visitors who are having this problem will find "their solution" in the other answers mentioning screen/byobu/tmux.
user.dz over 10 years

@Programster, yeah, Byobu is ex. screen. It has both byobu-screen and byobu-tmux.
Timur Fayzrakhmanov over 10 years

You are right.., but from my point of view, the basic concepts are more important to understand system working better and understand what you want and doing wrong. Thank you both!
Sandeep over 10 years

I recommend tmux as an alternative to screen.