You should look for modern alternatives like tmux.

tmux is superior to screen for many reasons, here are just some examples:

• Windows can be moved between session and even linked to multiple sessions
• Windows can be split horizontally and vertically into panes
• Support for UTF-8 and 256 colour terminals
• Sessions can be controlled from the shell without the need to enter a session

Basic Functionality

To get the same functionality as explained in the answer recommending screen, you would need to do the following:

• ssh into the remote machine
• start tmux by typing tmux into the shell
• start the process you want inside the started tmux session
• leave/detach the tmux session by typing Ctrl+b and then d

You can now safely log off from the remote machine, your process will keep running inside tmux. When you come back again and want to check the status of your process you can use tmux attach to attach to your tmux session.

If you want to have multiple sessions running side-by-side, you should name each session using Ctrl+b and $. You can get a list of the currently running sessions using tmux list-sessions or simply tmux ls, now attach to a running session with command tmux attach-session -t <session-name>.

tmux can do much more advanced things than handle a single window in a single session. For more information have a look in man tmux or the tmux GitHub page. In particular, here's an FAQ about the main differences between screen and tmux.

Consider reptyr:

NAME
       reptyr - Reparent a running program to a new terminal

SYNOPSIS
       reptyr PID

Find vim's process id with pidof vim or ps aux | grep vim.

It is also possible to see the process id if you try to open a file which is still opened by vim. Using the shown pid you should be able to reattach to your previous session.

If you get an error:

Unable to attach to pid 12345: Operation not permitted

Ensure that the ptrace scope is set to 0 (instead of 1):

echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope

After running reptyr, you may have to press Enter or another key to refresh the terminal (console) window.

The answer was noted in this post.

Sending an SIGUSR1 signal to the tmux process recreases the socket file, allowing you to reattach using tmux attach afterwards.

Since the PID of the running tmux command was 5612, I used:

$ sudo kill -SIGUSR1 5612
$ tmux attach

The name of the session is stored in the tmux variable #S, to access it in a terminal, you can do

tmux display-message -p "#S"

If you want to use it in .tmux.conf, it's simply #S. Note that the -p option will print the message on stdout, otherwise the message is displayed in the tmux status line.

If the above command is called inside a session, it returns the name of the session. If it is called outside any session, it still returns the name of the last still running session. I couldn't find a tmux command to check, if one is inside a session or not, so I had to come up with this work around:

tmux list-sessions | sed -n '/(attached)/s/:.*//p'

tmux list-sessions shows all sessions, if one is attached, it shows (attached) at the end. With sed we suppress all output (option -n) except where we find the keyword (attached), at this line we cut away everyhing after a :, which leaves us with the name of the session. This works for me inside and outside a session, as opposed to tmux display-message -p "#S".

Of course this works only if there is no : and no (attached) in the name of the session.

As commented by Chris Johnsen, a way to check if one is inside a tmux session is to see if its environment variable is set:

[[ -n "${TMUX+set}" ]] && tmux display-message -p "#S"