CURL 7.75 released: tool to transfer data from or to a server

curl is a tool to transfer data from or to a server, using one of the supported protocols (HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, DICT, TELNET, LDAP or FILE). The command is designed to work without user interaction.
curl offers proxy support, user authentication, FTP uploading, HTTP posting, SSL connections, cookies, file transfer resume, Metalink, and many other features.

CURL 7.75 released.

Changelog

Changes:

• curl: add –create-file-mode [mode]
• curl: add new variables to –write-out
• dns: extend CURLOPT_RESOLVE syntax for adding non-permanent entries
• gopher: implement secure gopher protocol
• http: add Hyper as new optional HTTP backend
• http: introduce AWS HTTP v4 Signature support

Bugfixes:

• badsymbols.pl: add verbose mode -v
• badsymbols.pl: ignore stand-alone single hash lines
• BUG-BOUNTY: minor language updates
• build: fix djgpp builds
• cleanup: fix empty expression statement has no effect
• cmake: Add an option to disable libidn2
• cmake: enable gophers correctly in curl-config
• cmake: expose CURL_DISABLE_OPENSSL_AUTO_LOAD_CONFIG
• cmdline-opts/gen.pl: return hard on errors
• cmdline-opts/retry.d: mention response code 429 as well
• configure: set -Wextra-semi-stmt for clang with –enable-debug
• connect: defer port selection until connect() time
• connect: mark intentional ignores of setsockopt return values
• connect: on linux, enable reporting of all ICMP errors on UDP sockets
• connect: zero variable on stack to silence valgrind complaint
• cookie: avoid the C1001 internal compiler error with MSVC 14
• curl.1: fix typo microsft -> microsoft
• curl: fix handling of -q option
• curl: include the file name in –xattr/–remote-time error msgs
• curl: move fprintf outputs to warnf

More…

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How to use curl

Basic GET

GET a single resource via its URI

The default operation is a GET:

curl http://api.example.com:8080/statuses/1234

GET multiple resources where IDs are in a range

Use square brackets with a dashed range:

curl http://api.example.com:8080/items/[1230-1234]

GET multiple resources where IDs aren’t in a range

Use curly braces with comma-delimited strings:

curl http://api.example.com:8080/products/{abc,def,ghi}/status

Using HTTP Headers

Accept only the application/json content-type

Use the header option: -H or –header

curl -H 'Accept: application/json' http://api.example.com:8080/items/1234

Add multiple headers

Use multiple -H options:

curl -H ‘Accept: application/json’ -H ‘Accept-Encoding: gzip’ http://api.example.com:8080/products/a1b2c3ef/status

Note: the output from this is likely to be unreadable because it’s gzipped!

More likely you’d use this with ETags:

curl -H ‘Accept: application/json’ -H ‘If-None-Match: “1cc044-172-3d9aee80″‘ http://api.example.com:8080/products/a1b2c3ef/status

Show the network and HTTP “conversation”

Use the verbose option: -v or –verbose

curl -v -H http://api.example.com

POST and PUT

POST data to a URI

To send data to the server, you use either POST or PUT, depending on what the API requires. To do a POST, you simply use the -d (–data)  with some content:

curl -d "name=Ted" http://api.example.com:8080/customers

Note that this uses application/x-www-form-urlencoded as the Content-Type, i.e.,as if it was submitted by an HTML Form. You can use multiple -d options, which will be combined, e.g., these two commands produce the same content:

curl -d “first=Ted” -d “last=Young” http://api.example.com:8080/customers
curl -d “first=Ted&last=Young” http://api.example.com:8080/customers

If you want to send JSON, you’ll need to specify the Content-Type explicitly using the -H (header) option:

curl -d '{"name": "Ted"}' -H 'Content-Type: application/json' http://api.example.com:8080/items

PUT data to a URI

If you need to use the PUT method, you’ll need to override the method with the -X (–request) option:

curl -X PUT -d ‘{“name”: “Ted”}’ -H ‘Content-Type: application/json’ http://api.example.com:8080/items/1234