How should one safely background a “daemon” process when started manually?

Question

I once used emacsclient as my editor from the command line, but it bothered me that it would hang the terminal window while I was working in emacs. I tried backgrounding the process by running emacsclient somefile.txt & but that lead to a lot of "broken pipes". I didn't know what those were, but my files were getting corrupted. I've learned to deal with the issue.

Recently, I also started using latexmk for compiling research papers. I tried latexmk -pvc & to run a continuously-compiling process in the background, but again I ran into the issue of "broken pipes".

While I'm usually in a tabbed terminal and can work around a busy window by starting a new one, I really like having my full command history. Since most commands get typed into the first terminal window, it has the best history.

But I keep finding myself working remotely on machines with no screen emulators. Is there a baked-in way to multitask in a single terminal window?

Answer 1

As far as I know, the only reason you would get a broken pipe with a backgrounded process is if you close the terminal window that started it. Even though it's in the background it's still attached to your terminal by pipes to stdin and stdout. If you close, log-out, or exit the terminal, the process's pipes will get broken, and the process will receive a signal to terminate (SIGHUP I believe).

The solution to this would probably be to use nohup. nohup redirects the new background process's stdin, stdout, and stderr to files and prevents the process from being sent SIGHUP.

To use it you can run nohup emacsclient somefile.txt & or if you want to avoid the nohup.out and nohup.err files that it uses to capture stdout and stderr, you can get rid of the output entirely with nohup emacsclient somefile.txt &> /dev/null &.

Since that gets a bit unwieldy to type just to edit a file, you will probably want to stick that in an alias or shell script.