Difference between curl calls

Question

What is the difference between this two curl calls:

curl -X POST -d "/path/file.txt" http://api-path
curl -X POST -d "@/path/file.txt" http://api-path

Answer 1

The first form sends the string "/path/file.txt" as data, probably not what you want. The @ makes curl interpret it as a filename to read from. See http://curl.haxx.se/docs/manpage.html, search for the "--data" option.