How to store curl response in bash script?

Question

I am trying to download file from hawkbit using curl in a bash script. Below is the curl invocation

curl --fail -sS -O -C - --location "${HEADERS[@]}" -w "%{http_code}\n" -X GET "$temp_url"

Now I want to store any error message from curl --fail if there is any to a variable. (example: curl: (22) The requested URL returned error: 416)

#!/bin/bash

response=$(curl --fail -sS -O -C - --location "${HEADERS[@]}" -w "%{http_code}\n" -X GET "$temp_url")
exit_status=$?
echo "exit status is $exit_status"
http_code=${response: -3}

if [ $exit_status -eq "0" ] && [ $http_code -eq "200" ] ; then
    echo "Success"
else
    echo "Failure"
    exit $exit_status
fi

Can anyone please let me know how should I improve the behavior of curl response?

P.S: Please let me know if any info is missing

Does this answer your question? [Capture stdout and stderr into different variables](https://stackoverflow.com/questions/11027679/capture-stdout-and-stderr-into-different-variables) — user1934428, Apr 03 '23 at 06:14

score 2 · Accepted Answer · answered Apr 02 '23 at 11:41

2

You are storing the "exit_status" before your curl command. This will always set it to the value 0. And your curl command doesn't seem to be complete either, but that's another matter.

answered Apr 02 '23 at 11:41

Swifty

180
7

What do you mean by "curl command doesn't seem to be complete? – Preeti Apr 02 '23 at 12:32
Well, nothing special. It just made me curious, because if I try your code as is, I sometimes get a 416... Besides that, have you fixed your code by moving the exit_status after the curl command? – Swifty Apr 02 '23 at 13:05
Yes, I have fxed it – Preeti Apr 02 '23 at 13:11
`curl` completes. 416 is an HTTP response code that indicates a problem with the request, not that the request hasn't been completed yet. (Oh, I caught the question just after it was edited to set `exit_status` after `curl`.) – chepner Apr 02 '23 at 13:12

Ed Morton · Answer 2 · 2023-04-02T18:58:59.947

I think what you're really asking for help with is how to store the error message from a curl failure, if any:

$ curl --fail 'foo:bar'
curl: (3) URL using bad/illegal format or missing URL

$ echo $?
3

curl Fail:

$ { response=$( curl --fail 'foo:bar' 2>&1 >&3 3>&-); } 3>&1

$ echo $?
3

$ echo "$response"
curl: (3) URL using bad/illegal format or missing URL

curl Success:

$ { response=$( curl --fail 'http://example.com' 2>&1 >&3 3>&-); } 3>&1
<!doctype html>
<html>
<head>
    <title>Example Domain</title>

    <meta charset="utf-8" />
    <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <style type="text/css">
    body {
        background-color: #f0f0f2;
        margin: 0;
        padding: 0;
        font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;

    }
    div {
        width: 600px;
        margin: 5em auto;
        padding: 2em;
        background-color: #fdfdff;
        border-radius: 0.5em;
        box-shadow: 2px 3px 7px 2px rgba(0,0,0,0.02);
    }
    a:link, a:visited {
        color: #38488f;
        text-decoration: none;
    }
    @media (max-width: 700px) {
        div {
            margin: 0 auto;
            width: auto;
        }
    }
    </style>
</head>

<body>
<div>
    <h1>Example Domain</h1>
    <p>This domain is for use in illustrative examples in documents. You may use this
    domain in literature without prior coordination or asking for permission.</p>
    <p><a href="https://www.iana.org/domains/example">More information...</a></p>
</div>
</body>
</html>

$ echo $?
0

$ echo "$response"

See https://unix.stackexchange.com/a/474195/133219.

How to store curl response in bash script?

2 Answers2