yank:tldr:3eda3

This command consists of two parts: ${echo hello=world} and | yank -d ${=}.

${echo hello=world}: This part is using parameter expansion syntax in bash. It assigns the value "world" to the variable "hello" and then echoes or prints the string "hello=world". Essentially, it outputs the text "hello=world".

| (pipe symbol): It is a pipe operator that takes the output of the command on its left side and provides it as input to the command on its right side. It allows the output of one command to be passed as input to another command.

yank -d ${=}: This part uses the yank command with the -d option and ${=} as the argument. ${=} is another parameter expansion syntax that represents all positional parameters as a single word.

The yank command is generally used to capture or copy output into the clipboard or selection buffer. So, in this case, it would capture the output "hello=world" from the previous command and store it in the clipboard or selection buffer.