mlr:tldr:b88a4

The command you provided has two parts separated by the pipe symbol |.

1. The first part is echo '{"hello":"world"}'. It uses the echo command to output the string {"hello":"world"}. The purpose of this part is to provide input data for the subsequent command.

2. The second part is mlr --ijson --opprint cat. This is a command that uses a tool called mlr with specific options and the cat command.

• mlr is a command-line tool for processing structured data such as CSV, JSON, etc.
• --ijson is an option for mlr that specifies the input is in JSON format.
• --opprint is another option for mlr that formats the output in a pretty-printed, human-readable form.
• cat is a command used in Unix-like systems to concatenate and display the contents of files.

Therefore, when you execute the entire command, it will take the JSON string {"hello":"world"}, pass it as input to mlr, which will interpret it as JSON, then format and output it in a more readable form.