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Thomas Browne
Asked: 2018-10-29 10:14:15 +0800 CST

Can I redirect a file to the terminal? [duplicate]

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I know I can redirect all terminal output to a file, but does that work the other way around?

Can I have a terminal window open, in Tmux or elsewhere, that is receiving redirected output from a file in real time? IE if another process is writing to the file, this is being directed to a terminal window?

Use case: REPL swamped by output

The reason I would like this is I would like to see the output of some code in a REPL (Erlang it turns out) which has many processes creating terminal output stuff in background, but this output is very rapid and I "lose" my REPL command line constantly as it is drowned by the output. So I'd like those processes to output to a file instead, but, in another terminal, I still want to see what that output is in real time.

command-line redirect

1 Answers

  1. tail -f is what I was looking for. 

    touch ~/foo
tail -f ~/foo

    now in another terminal:

    echo "hello" >> ~/foo
echo "there" >> ~/foo

    Works a charm. Now some programs (vim for example) will close and reopen the file and tail -f will not work, so you will not see additions when you save from vim. In this case, use tail -F, which explicitly follows the filename rather than the descriptor.

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