Hi,

I am just wondering what happens to an SSH session when a power outage occurs on your client PC. If I am SSH'd in an running an script that takes a long time and your connection abruptly ends does the command finish running or cancel as soon as the connection stops? Does it depend on the type of connection?

Say I ssh in using:
And once in I run the script test.sh, which takes ~10min to complete
If my client PC is switched off 30sec into running this command is ~/output just filled with whatever was output up until 30sec?

^ i think so. check out the nohup command.

Thanks heaps schneidz, did the trick

"HUP" stands for "Hang Up," as in "(300 baud) teletype modems." The user switched-off the terminal or hung-up the phone ... or their cat did it, as the case may be. Or, you disconnected the SSH, or closed the window, or what have you. "Bottom line is, you went away." SIGHUP will be sent to all processes. Their ordinary response is to terminate.

The "nohup" command instructs the process to ignore this signal: to keep running.

Another option is to run your command inside "screen". With nohup, once you press enter, the process is "gone". By that I mean if it prompts you for something, pauses, etc., there's nothing you can do it interact with it again. With screen, you can disconnect and reconnect to the shell session that's running the script whenever you want. Of course the disadvantage of screen is that even when the process finishes, the screen session will still be sitting there waiting for you to close it, with nohup it'll just exit quietly.

Which method you should use depends on the process you're running. For the process in this thread, I agree that nohup is probably the better option, but there are many other instances where screen would be better suited.