如何减少Curl命令的output？

Question

Am looking for a way to restrict the output of curl command

For example when using curl to check if port is open on server, just want to restrict the output to first lines to confirm that port is open

curl -v host:1521 want to just display first 3 lines of output *About to connect to *Trying host..connected * Connected to host

Answer 1

Why not to pipe it to head ?

curl -v host:1521 | head -n3

where -n3 means 3 lines from top.

EDIT:

As discussed in comments you use -v option to capture headers etc. which are printed on stderr instead of stdout so head doesn't affect it. You have to redirect stderr to stdout and after that operate on:

curl -v www.example.com 2>&1 | grep Connected

This will return * Connected to www.example.com (IP_ADDRESS_HERE) port 443 (#0) if connected successfully and nothing otherwise.