cowsay:tldr:a61fb

The command echo "${hello, world}" | cowsay is a combination of the echo command and the cowsay command.

1. echo is a command in Unix-like operating systems that is used to display text or variables to the terminal. In this case, "${hello, world}" is the argument provided to echo. The double quotes are used to include the whole string as a single argument.

2. The expression ${hello, world} is using brace expansion in the shell. It expands to two words: "hello" and "world". The comma inside the braces represents the expansion operator.

3. The | symbol is a pipe operator that links the output of the echo command to the input of the cowsay command. It allows the output of one command to be used as the input for another command.

4. cowsay is a program that generates ASCII art of a cow with a speech bubble containing the input text. It takes the input from the echo command and displays the ASCII art in the terminal.

So, when you run echo "${hello, world}" | cowsay, it will display the ASCII art of a cow saying "hello world".