ftp:tldr:4672b

This command is using a shell scripting technique to delete multiple files that end with the ".txt" extension.

Here's a breakdown of the components:

• mdelete: This is a command used to delete files. It might be specific to a certain command-line tool or program.
• ${-txt}: This is a shell parameter expansion technique. The "$" refers to all the positional parameters passed to the script or command. The "-" is used to separate the positional parameters. The "-txt" is a string appended to each positional parameter, effectively adding the ".txt" extension.
• The combination of ${*-txt} expands to a list of files that end with ".txt", obtained by appending "-txt" to each positional parameter.

Overall, this command will delete all the files provided as positional parameters (arguments) if their names end with ".txt".