How do I nohup a here document in the background from within a ksh script? - background

Question

I have a ksh script that comes to a point where it must run a long running command. The long running command is executed via a heredoc in the script presently. I want to throw the command (represented by cat in my samples below) into the background but only after taking its input from the heredoc. Since the "nohup cat.." finishes instantaneously and I see an empty nohup.out file, I am not sure the script is doing what I need it to do, which is to spawn a nohupped version of the heredoc command and exit, leaving the command to run for however long it takes to complete.
I am using cat as the "command" since it too sits there and just waits for console input.
Working version without nohupping:
#!/bin/ksh
cat << EOF
Hello
World
HOw are you!
EOF
Trying to nohup the heredoc:
#!/bin/ksh
nohup cat <<EOF
Hello
World
HOw are you!
EOF
Seems to work, output is going into nohup.out as expected. But now, how to throw that into the background? I tried the below (and many variations of it) :
#!/bin/ksh
nohup cat & <<EOF
Hello
World
HOw are you!
EOF
but, nohup.out is empty, so I am not sure what the above is doing. There is no running "cat" in the background which tells me it ran and completed at least - or maybe didn't run at all. No other variation I can invent for trying to throw the heredoc into the background from my ksh script works.
Any suggestions on a way to achieve this using heredoc?

Answer 1

Here are two options.
You could try wrapping the nohup sequence inside a function, which may look cleaner, and then invoking that function with the trailing ampersand.
Using a function, like this:
#!/bin/ksh
function dostuff
{
nohup cat <<- END
Hello
World
How are you!
END
}
dostuff &
wait
You can also try wrapping the commands to be backgrounded into a grouping { } block, separating each command with a ; inside the brackets, and then backgrounding that block via:
{ nohup cat <<- EOF
...
EOF
; whatever
} &