How can I curl a URL by using a string from a file?-CodePudding

I have a "testing.txt" file that has this following string

example.com

i want to curl that url by using this command

curl $testing.txt

and i expect to get this output

<!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>

so the question is, how can i curl a URL by using a string that in a file?

CodePudding user response：

Basically, To read content file:

cat the_file_to_read

So,

curl --url "$(cat the_file_to_read)" --output "the_file_to_write"

Of course, the input file content must be contains the complete URL... or not. You could add the protocol in cURL command:

curl --url "https://$(cat the_file_to_read)" --output "the_file_to_write"

To prevent more than one line in input file, you need one or mode filters like that:

curl --url "https://$(cat the_file_to_read | head -1)" --output "the_file_to_write"

You also can read HTTP response code like this:

HTTP_RESPONSE_CODE=$(curl --url "https://$(cat the_file_to_read | head -1)" --output "the_file_to_write" --write-out '%{response_code}')
echo "HTTP_RESPONSE_CODE=${HTTP_RESPONSE_CODE}"

See man curl for more explanations, more options...