How to send line break with curl?

I've tried the following to send a line break with curl, but \n is not interpreted by curl.

curl -X PUT -d "my message\n" http://localhost:8000/hello

How can I send a line break with curl?

Sometimes you want to provide the data to be sent verbatim.

The --data-binary option does that.

Your shell is passing \ followed by n rather than a newline to curl rather than "my message\n". Bash has support for another string syntax that supports escape sequences like \n and \t. To use it, start the string with $' and end the string with ':

curl -X PUT -d $'my message\n' http://localhost:8000/hello

See ANSI-C Quoting in the Bash Reference Manual

There's a much easier way!

curl -X PUT -d $'my message\n' http://localhost:8000/hello

This will use ANSI-C Quoting to insert the newline character.

No piping, no data files. See also Sending Newlines with cURL.