How to Pipe or Redirect the Output of Curl -V

How do I pipe or redirect the output of curl -v?

add the -s (silent) option to remove the progress meter, then redirect stderr to stdout to get verbose output on the same fd as the response body

curl -vs google.com 2>&1 | less

Getting a piped curl command output to a variable in bash

You need to remove the -o option that writes the output to a file, in your case /dev/null. Here is your updated code that should work.

$ response=$(curl -k -x $i:1234 -U $u:$p -w $outputformat -s $site | cut -d ' ' -f 2)

Another way to check is to remove pipe and send your STDERR to /dev/null. This will show you what is getting passed to your cut command.

You should see something if all is happy.

$ curl -k -x $i:1234 -U $u:$p  -s $site 2>/dev/null

If you don't get any output, then remove the STDERR redirect and echo the return code.

$ curl -k -x $i:1234 -U $u:$p  -s $site
$ echo $?
0

If the exit code is anything other then 0 you have an error. You can find the error codes in the man page or this site has pretty good write up.

No to get the response code.

$ curl  -w "HTTP Response: %{http_code} - URL: %{redirect_url}\n"  -o /dev/null  -s http://yahoo.com/
HTTP Response: 301 - URL: https://yahoo.com/
$  curl  -w "%{http_code}\n"  -o /dev/null  -s http://yahoo.com/
301
$ response=$(curl  -w "%{http_code}\n"  -o /dev/null  -s http://yahoo.com/)
$ echo $response
301
$  curl  -w "%{http_code}\n"  -o /dev/null  -s http://yahoo.com/ | cut -d' ' -f3
301
$ response=$( curl  -w "%{http_code}\n"  -o /dev/null  -s http://yahoo.com/ | cut -d' ' -f3)
$ echo $response
301

Redirect curl to while loop

You will want to redirect the output of curl using process substitution as follows:

while read -r l; do 
    echo "123 $l"
done < <(curl 'URL')

You can also use the output of a quoted command substitution and a herestring as follows:

while read -r l; do 
    echo "123 $l"
done <<<"$(curl 'URL')"

(though process substitution is preferred)

note: for redirecting to a file, you can redirect the output of a block, rather than a line at a time:

:>outfile    ## truncate outfile if it exists
{
    while read -r l; do 
        echo "123 $l"
    done < <(curl 'URL') 
}>outfile

Curl with pipe : How to print the error without the progress-meter?

The flag you are looking for is -sS. From man curl:

   -s, --silent
          Silent  or  quiet  mode.  Don't  show progress meter or error messages.  Makes Curl mute. It will still output the data you ask for, potentially even to the terminal/stdout
          unless you redirect it.

          Use -S, --show-error in addition to this option to disable progress meter but still show error messages.

          See also -v, --verbose and --stderr.

Curl to return http status code along with the response

I was able to get a solution by looking at the curl doc which specifies to use - for the output to get the output to stdout.

curl -o - -I http://localhost

To get the response with just the http return code, I could just do

curl -o /dev/null -s -w "%{http_code}\n" http://localhost

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