open:tldr:037e2

The command "open -R ${filename}" is a command typically used in macOS or OS X Terminal. Here's an explanation of each part:

1. "open": It is a command-line utility in macOS that opens files, folders, or applications using the default app associated with the file type.
2. "-R": It is an option for the "open" command, which opens the file or folder in the default application, but with the focus on the object in Finder (the default file manager application in macOS).
3. "${filename}": It is a placeholder for the actual file name or path. You would replace "${filename}" with the name of the file you want to open.

By using this command, the specified file will be opened in the default application, and the Finder window will automatically select that file, making it easier for a user to locate it visually.