How can I run program from terminal without killing the program when closing the terminal [duplicate]
Some GUI apps launch cleanly via the Terminal command line, but some don't, and they cause the Terminal to wait for the app to terminate. Even then, some don't "release" the command line.
The mysterious ampersand & suffix seems to cause the terminal to put the process into the background (but I'm not sure what happens there).
Is there a way to launch an app via the Terminal so that there is no "hang on" effect, just like launching something via Alt+F2?
I'd like to have the command line available again immediately, without something still in the background and printing in the terminal.
Suppose gedit is the program you want to run detached (aka. "disowned", "disentangled", "decoupled"). There are different ways depending on what you want to do exactly:
Program already running
Disown:
disown -h is the way to go if you want to do that with an already running program (i.e. if you forgot to nohup it). You first have to stop it using Ctrl+Z. Then you can put in in the background using bg [jobId] (e.g. bg 1). You get a list of running jobs with their jobId using jobs. After that you can decouple it from terminal using disown -h %[jobId]. Example terminal session:
$ gedit
^Z
[1]+ Stopped gedit
$ jobs
[1]+ Stopped gedit
$ bg 1
[1]+ gedit &
$ disown -h %1
$ exit
Program not started yet
nohup
nohup is not always present on all machines. If you know you want to decouple beforehand you would use:
nohup gedit &
Maybe you will want to redirect the shell output as well and your program a pseudo input source, so: nohup ./myprogram > foo.out 2> bar.err < /dev/null &. You would want to redirect the output to either not be annoyed by it or to use it later. The null-input can help to prevent hickups in ssh an such.
Subshell:
You can achieve a similar effect by
$ (geany >/dev/null 2>&1 &)
The brackets open a new subshell to run gedit in. The >/dev/null 2>&1 redirects the shell output to nowhere (suppressing the output). And the & at the end puts the process in the background.
Terminal multiplexing
Also terminal multiplexing using screen or byobu. You basically run the program in a terminal of its own. I can really recommend byobu for other reasons too. Below is a list of boybu-shortcuts that might come in handy for your first steps:
Useful:
- F2 Create a new window
- F3 Move to the next window
- F4 Move to the previous window
- F6 Detach from the session and logout
- Shift-F6 Detach from the session, but do not logout
- F7 Enter scrollback/search mode
- Ctrl-F5 Reconnect any SSH/GPG sockets or agents
Less useful:
- Shift-F2 Split the screen horizontally
- Ctrl-F2 Split the screen vertically
- Shift-F3 Move focus to the next split
- Shift-F4 Move focus to the previous split
- Shift-F5 Collapse all splits
- F5 Refresh all status notifications
- F8 Rename the current window
- F9 Launch the Byobu Configuration Menu
- F12 GNU Screen's Escape Key
- Alt-Pageup Scroll back through this window's history
- Alt-Pagedown Scroll forward through this window's history
- Ctrl-a-! Toggle all of Byobu's keybindings on or off
The 'at' daemon and others
at is a nice useful little tool to run a command at a scheduled time. It can be 'misused' to detach a command from the shell:
echo './myprogram myoption1 myoption2' | at now
Also you can look into setsid and start-stop-daemon, but the other methods should suffice.
To start an application and detach it from the launched terminal use &!.
firefox &!