curl:tldr:feb19

The given command is using the curl command-line tool, which is commonly used to send HTTP requests and receive responses from a server. Here is the breakdown of the command:

• curl: The command itself to initiate an HTTP request.

• --header ${'X-My-Header: 123'}: This option is used to specify an additional header for the request. In this case, it sets a custom header named X-My-Header with the value 123. The ${...} syntax is commonly used in shell scripting to interpolate variables, but in this case, it seems unnecessary as there are no variables involved in this command.

• --request ${PUT}: This option specifies the HTTP method for the request. In this case, it uses the ${PUT} value, which is expected to be a variable. Again, the use of ${...} does not seem to serve any purpose here.

• ${http:--example-com}: This appears to be an incorrect usage of the variable substitution. It seems that the intention is to provide the URL for the request. However, the ${...} syntax used is not correct and it is missing the proper quotes (" or ') to denote a string value. It should be something like http://example.com.

In summary, the command seems to have incorrect usage of variable substitution and the URL is not provided correctly. The correct usage should be:

curl --header 'X-My-Header: 123' --request PUT 'http://example.com'