edit:tldr:00be6

The command "run-mailcap --action=edit ${filename}" is used to open a file for editing. Here's a breakdown of the command:

• "run-mailcap" is a command-line program used to retrieve the preferred action associated with a given filename based on the mailcap configuration file.
• "--action=edit" is an option provided to the "run-mailcap" command, specifying that the desired action is to edit the file.
• "${filename}" is a placeholder for the actual name of the file you want to edit. This should be replaced with the specific file name you want to work on.

So when this command is executed, it will use the mailcap configuration to determine the program or utility that should be used to edit the specified file, and launches it.