Curl
Internal
Overview
If the server responds with 404, curl displays the error message, is any, and exits with 0.
Installation
With apt
apt-get update apt-get install curl
Exit Code
Command Line Configuration
-X
The HTTP method.
-H
Specifies a request header. Multiple headers can be specified. Example:
curl -H "Authentication Bearer: <token>" -H "Content-Type: application/json" ...
Quiet Mode
-s|--silent
Content-Type
-H "Content-Type: application/json"
-u, --user
Authentication:
curl -u username:password
If no password is specified after ":", curl will challenge for password.
--basic
Basic Authentication
Basic Authentication when Having the Basic Authorization Token
The basic authorization token can be used directly, as shown:
curl -H "Authorization: Basic c[...]4" https://jenkins.example.com/cloud/job/example/job/somejob/33/consoleText > ./build-33.txt
--digest
Digest Authentication
-k --insecure
Insecure.
-v
Verbose. Shows more details about the request and response. A line starting with '>' means "header data" sent by curl, '<' means "header data" received by curl that is hidden in normal cases, and a line starting with '*' means additional info provided by curl.
-s, --silent
Turns on silent or quiet mode. In silent mode curl does not show progress meter or error messages.
-S, --show-error
Like silent more, it disables progress meter, but shows error messages.
-i
Show the HTTP headers in the output.
-A
Specify the User-Agent string to send to the HTTP server. To encode blanks in the string, surround the string with single quote marks. This can also be set with the -H header option. If this option is used several times, the last one will be used.
-d
Sends the specified data in a POST or PUT request to the HTTP server, in the same way that a browser does when a user has filled in an HTML form and presses the submit button. This will cause curl to pass the data to the server using the content-type application/x-www-form-urlencoded.
If the option is used more than once on the same command line, the data pieces specified will be merged together with a separating &-symbol. Thus, using "-d name=alice -d qualification=coder" would generate a post chunk that looks like 'name=alice&qualification=coder'.
If data starts with the letter @, the rest should be a file name to read the data from, or - if you want curl to read the data from stdin. Multiple files can also be specified. When --data is told to read from a file like that, carriage returns and newlines will be stripped out. If you don't want the @ character to have a special interpretation use --data-raw instead.
-d and GET
If -d is used with GET, the data is sent as a entity body.
--data-binary
If what follows after --data-binary starts with @, it is considered to be a name of a file, and the content of the file is sent as data.
curl ... --data-binary @./some-file.json ...
echo "some_metric 1.0" | curl --data-binary @- http://localhost:9091/metrics/
-I
HEAD only.
-L, --location
If the server reports that the requested page has moved to a different location (indicated with a Location: header and a 3XX response code), this option will make curl redo the request on the new place.
-F, --form
Specify HTTP multipart POST data. See Upload a file with POST.
-T, --upload-file
Transfer the specified local file to destination
-O, --remote-name
Write output to a file named as the remote file.
-o, --output <file>
Write to file instead of stdout:
curl -o /tmp/somefile.txt https://......
-n, --netrc
See .netrc below.
Secure Connection
curl https://logging-es:9200/ --capath /etc/kibana/keys --key /etc/kibana/keys/key
Download a file and write it locally
-O instructs curl to write output to a local file name like the remote file we get. Only the file part of the remote file is used. The file will be saved in the current directory. If you want the file saved in a different directory, make sure you change the current working directory before invoking curl with this option.
curl -O http://ftp.gnu.org/gnu/wget/wget-1.15.tar.gz
Upload a file with POST
curl -X POST -F 'file=@./something.tgz'
Send REST invocations
GET
curl -X GET http://localhost:8080/novaordis-paas/project/
POST
curl -H "Content-Type: application/json" -X POST \
-d '{"id":"1","name":"MyProject","team":"A","language":"java","size":"small"}' \
http://localhost:8080/novaordis-paas/project/MyProject
echo "some_metric 1.0" | curl --data-binary @- http://localhost:9091/metrics/
Also see Upload a file with POST.
PUT
curl -X PUT -d arg=val -d arg=val http://localhost:8080/novaordis-paas/project/MyProject
DELETE
curl -X DELETE http://localhost:8080/novaordis-paas/project/MyProject
Simulation of a HTTP Session JSessionID
curl -b "JSESSIONID=e1VBIIBFhyjU2PLU0JFNwqYu" http://localhost:8080/session-servlet/
Parallel Instances
i=0; while [ $i -lt 20 ]; do (curl http://localhost/&); ((i++)); done
Use curl with a Proxy
It is sometimes useful to configure curl to send request via a proxy. This is achieved with
curl -x http://<proxy-host>:<proxy-port>
To use curl with Charles, see: