Shulou(Shulou.com)06/02 Report--

Curl is an open source file transfer tool that uses URL syntax to work on the command line. It is widely used in Unix and various Linux distributions.

There is also a portable version under the Windows system.

Curl is particularly widely used in the installation script of many open source software and frameworks on github, such as minikube, a native running tool of Kubernetes.

There is a command in the installation script:

Curl-Lo kubectl https://storage.googleapis.com/kubernetes-release/release/$(curl-s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl & & chmod + x kubectl & & sudo cp kubectl / usr/local/bin/ & & rm kubectl

The following url opens in a browser and finds that the txt file only maintains an up-to-date version number:

Https://storage.googleapis.com/kubernetes-release/release/stable.txt

So the placeholder defined by $in the following url

Https://storage.googleapis.com/kubernetes-release/release/$(curl-s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl

Will be replaced with v1.11.2:

The final downloaded url:

Https://storage.googleapis.com/kubernetes-release/release/v1.11.2/bin/linux/amd64/kubectl

Another use of curl is to download the source code of the specified url, such as curl http://www.baidu.com

ABAP has a similar tool, function module HTTP_GET:

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