Using nohup when initial input is required

Question

On a linux system is there any way to use nohup when the process that is being nohuped required input, such as an rsync command that needs a password to be entered but will then run happily on its own?

Answer 1

If the command doesn't have to be scripted, you can do it this way:

1. run it in the foreground
2. pause it (CTRL+Z)
3. disown it so that it won't be closed when you close your shell (disown -h %jobid)
4. resume the job in the background (bg %jobid)

Answer 2

You want to look at screen. Screen will create a shell session for you, which you can detach and then reattach at a later date. Try:

 # screen rsync -a directory server@directory

You can type in your password, verify that it's running as you expect and then press 'ctrl-a' followed by 'd'. You should now be detached from your screen session. If you want to see how it's getting on, run

 # screen -r

and you should be reattached. 'ctrl-a' 'd' will detach you again.

When the command finishes, screen should quit.

Answer 3

If possible it might be better for the specific instance of running an rsync command to set up SSH key authentication without a password rather than try to automatically stuff a password into rsync.

Answer 4

Some modules on the remote daemon may require authentication. If so, you will receive a password prompt when you connect. You can avoid the password prompt by setting the environment variable RSYNC_PASSWORD to the password you want to use or using the --password-file option. This may be useful when scripting rsync.

found this in the man page

Answer 5

Aside from what's been said above, the most general solution might be to wrap the command in a script that takes input from a file and passes it on (perhaps using pipes, or expect, or something like that). The wrapper script itself is then just a normal command that doesn't require input, of course.

Answer 6

The (very late) answer is:

Yes, you can use nohup with a process that requires input:

A: You can either start your process as you would usually:

• So you type nohup ... & like so:

  nohup rsync -av [email protected]:/from/here/ ./to/here &
  

  Now when you hit enter the process will start but is detached so you are in the situation you encountered and previewed as a problem: How to enter the credentials for user john at doe.io?

• Type jobs in your terminal and you will see something like:

  [1]+  Stopped                 nohup rsync -av [email protected]::/from/here/ ./to/here
  

  The [1]+ indicates the jobid (here it is just 1). Also, the process in now actually halted since the rsync command is waiting for input, hence the Stopped state.

• Type fg %<jobid> so in the example it would be fg %1 (don't forget the %, it's part of the syntax!)

• Now you brought the process to the foreground and can interact with it.

B: Or simply ditch the ampersand, so the process stays in the foreground (and you essentially follow the the accepted answer by @Joril).

• So you would type:

  nohup rsync -av [email protected]:/from/here/ ./to/here
  

  And you readily can interact with the process.

---

In both cases, A or B, now you can interact with the process:

• In our example the last line of in your terminal would now read something like:

  [email protected]'s password: 
  

• Once you are done interacting hit Ctrl + Z which will halt the process

• Type jobs and you will see something like:

  [1]+  Stopped                 nohup rsync -av [email protected]::/from/here/ ./to/here
  

• The only thing now left to do is to make the process running again. To do so simply type: bg %<jobid> (so bg %1 in our example).

• We are done! Go grab a coffee and and check your nohup.out file from time to time to see if the process has finished.