joe:tldr:5f011

This command appears to be using the text editor "joe" to open a file with a filename specified by a variable. The variable is represented as "${filename}", indicating that it will be replaced with an actual filename value when the command is executed.

Here's a step-by-step breakdown of the command:

1. "joe" is the name of the text editor being invoked. It could be a command-line editor available on the system.
2. "${filename}" is a placeholder for a variable. It suggests that the actual filename will be substituted into the command at runtime.
3. The variable "filename" represents the file name that should be opened with the text editor.
4. When the command is executed, the value of the "filename" variable will be substituted into the command, and the text editor will attempt to open that file for editing.