shell: how to make tail of a file running in background

Question

I want to run a few tasks in shell.

1. tail a file into a new file: for example: tail -f debug|tee -a test.log
2. at the same time, run other tasks.

My question is: how to make the command tail -f debug|tee -a test.log run in background, so that I can run other tasks then in shell script?

Answer 1

You don't need tee at all for this, just use the shell's built-in append operator:

tail -f debug >> test.log &

The trailing & works as normal in the shell. You only need tee to send the output to a file as well as standard out, which if you have it in the background probably isn't what you want.

Answer 2

Normally you just use an ampersand after the command if you want to background something.

tail -f debug|tee -a test.log &

Then you can bring it back to the foreground later by typing fg. Did this answer your question or have I missed what you were asking?