How do I pipe the output of a file to a command?

Question

I'm trying to do something a bit like:

cat my_key.pub | send_key_to_server

It led me to try experiment as such:

cat my_key.pub | echo

which produced no output.

Finally I tried:

echo "hello" | echo

which also produced no output. I would have expected it to say "hello". Why doesn't this work?

Answer 1

尝试

cat my_key.pub | xargs echo