TopolearnFetching a URL from the terminal is the starting point for testing APIs and downloading anything.
In its simplest form, curl https://example.com sends an HTTP GET request and writes the response body to standard output. Response headers are not shown by default.
Saving output:
-o filewrites the body to a file you name.-O(capital) uses the file name from the URL:curl -O https://example.com/app.tar.gzsavesapp.tar.gz. Add-Jto prefer the name the server suggests inContent-Disposition, and--output-dir dirto choose the directory.
When output goes to a file or pipe, curl shows a progress meter on stderr. -s (silent) hides it, and -sS hides it but still prints errors, the usual choice in scripts.
Redirects are not followed by default: a URL that answers 301 Moved Permanently gives you that short response. Add -L to follow Location headers to the final resource; downloads from GitHub releases and many CDNs need it.
Query strings are part of the URL. Quote URLs containing &, ? or [, otherwise your shell interprets them: curl 'https://api.example.com/search?q=cat&limit=5'.
curl --version shows the version, the TLS library and the protocols and features (HTTP2, HTTP3, ...) your build supports.
Example
curl https://example.com # body to stdout
curl -sS -o page.html https://example.com # save, quiet but show errors
curl -LO https://github.com/jqlang/jq/releases/download/jq-1.7.1/jq-linux-amd64
curl -L -o jq --output-dir ~/bin https://github.com/jqlang/jq/releases/download/jq-1.7.1/jq-linux-amd64
curl 'https://api.example.com/search?q=cat&limit=5' # quote the URL!
curl -sS https://api.github.com/repos/curl/curl | head -5
curl --version | head -1 # curl 8.x (...) libcurl/8.x OpenSSL/3...Remember
- curl URL = GET, body to stdout
- -o name / -O remote name; -L follows redirects
- -sS: no progress meter, but still show errors
Watch out for
- Forgetting -L and saving a tiny redirect page instead of the file.