concept: only 1 foreground program can be running on a shell terminal, however several can run in the background. Here’s how.

• [program] &
  launches the program directly into the background
• CTRL+Z
  suspends the program currently running in the foreground into stopped state into the background
• jobs -l
  lists current background programs
• fg %[n]
  puts into foreground the job number [n]
• bg %[n]
  makes program [n] run into the background. The program should already be backgrounded, however after CTRL+Z it is in stopped state, thus this command brings it back to running state
  an alternative solution is command
  kill -cont pidnr
• there are stopped jobs
  error message while attempting to log out notifies you that there are some jobs still hanging around. Use jobs and fg %[n] to terminate them correctly without data loss
• kill %[n]
  terminates [n] job
• logout logout
  logs out terminating all backgrounded jobs
  NOTE: with this command only backgrounded jobs in stopped state will be terminated, not those in running state.

screen

screen is a tty detachable emulator. you can use it with command
screen [program] args
to list all program executed with screen command
screen -list
to reattach a program executed with screen command (pid is taken from previous command)
screen -r [pid][tty][host]

shortcuts are
CTRL+ad  to detach a program using screen
CTRL+DD to detach a program using screen and logout (notice the capital D)

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3. Basic commands for GNU/Linux – BSD (part 1)
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6. Basic commands for working with VI (and VIM)
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