# cURL

## TL;DR

```sh
# Send a single GET request and show its output on stdout.
curl 'http://url.of/file'

# Be quiet.
curl --silent 'https://www.example.com'
curl -s --show-error 'https://www.example.com'

# Download files.
curl 'http://url.of/file' -o 'path/to/file'
curl -O 'http://url.of/file1' -O 'http://url.of/file2'
curl http://url.of/file[1-24]

# Resume downloads.
curl -C - -o 'partial_file' 'http://url.of/file'

# Limit downloads bandwidth.
curl --limit-rate '1000B' -O 'http://url.of/file'

# Follow redirects.
curl -L 'http://url.of/file'

# Only fetch HTTP headers from a response.
curl -I 'http://example.com'

# Only return the HTTP status code.
curl -o '/dev/null' -w '%{http_code}\n' -s -I 'http://example.com'

# Send different request types.
curl --request 'PUT' 'http://example.com'

# Specify headers.
curl 'http://example.com' -H 'Content-Type:application/json'

# Fail fast with no output.
# Returns the HTTP error code.
curl -f 'http://example.com'

# Skip certificate validation.
curl --insecure 'https://example.com'

# Pass certificates for a resource.
curl --cert 'client.pem' --key 'key.pem' -k 'https://example.com'
curl --cacert 'ca.pem' 'https://example.com'

# Authenticate.
curl -u 'username':'password' 'http://url.of/file'
curl -u 'username':'password' -O 'ftp://url.of/file'
curl 'ftp://username:password@example.com'

# POST to a form.
curl -F 'name=user' -F 'password=test' 'http://example.com'
curl --data 'name=bob' 'http://example.com/form'

# Send data.
curl 'http://example.com' -H "Content-Type:application/json" -d '{"name":"bob"}' -X 'POST'
curl … -d @file.json

# Use a proxy.
curl 'http://example.com' --proxy 'socks5://localhost:19999'

# Forcefully resolve a host to a given address.
curl 'https://example.com' --resolve 'example.com:443:google.com'
```

## Apply settings to all connections

Unless the `-q` option is used, `curl` always checks for a default config file on invocation and uses it if found.

The default configuration file is looked for in the following places, in this order:

1. `$CURL_HOME/.curlrc`
1. `$XDG_CONFIG_HOME/.curlrc`, added in 7.73.0
1. `$HOME/.curlrc`
1. on Windows only: `%USERPROFILE%\.curlrc`
1. on Windows only: `%APPDATA%\.curlrc`
1. on Windows only: `%USERPROFILE%\Application Data\.curlrc`

On Non-Windows hosts, `curl` uses `getpwuid` to find the user's home directory.

On Windows, if curl finds no `.curlrc` file in the sequence described above, it will check for one in the same dir the curl executable is placed.

```txt
# ~/.curlrc
# Accepts both short and long options.
# Options in long format are accepted without the leading two dashes to make it
# easier to read.
# Arguments must be provided on the same line of the option.
# Arguments can be separated by space, '=' and ':'

location
--insecure
--user-agent "my-agent"
request = "PUT"
config: "~/.config/curl"
```

## Sources

- [cheat.sh]
- [How to ignore invalid and self signed ssl connection errors with curl]
- [Config file]

[cheat.sh]: https://cheat.sh/curl
[config file]: https://everything.curl.dev/cmdline/configfile
[how to ignore invalid and self signed ssl connection errors with curl]: https://www.cyberciti.biz/faq/how-to-curl-ignore-ssl-certificate-warnings-command-option/
