aspell:tldr:47bf9

This command uses two Unix command-line utilities, cat and aspell, to list misspelled words in a file.

Here's the breakdown:

1. cat ${filename}: cat is a command that concatenates and displays the contents of a file. ${filename} is a placeholder for the actual name of the file. This part of the command is used to read the contents of the specified file and pass them as input to the next command.
2. |: This symbol represents the pipe operator, which redirects the output of the preceding command to the input of the next command.
3. aspell: aspell is a command-line spell checker utility.
4. --personal=${personal-word-list-pws}: --personal is an option for aspell command, used to specify a personal word list file. ${personal-word-list-pws} is a placeholder for the actual name of the personal word list file. By including this option, aspell will use the specified personal word list along with its default dictionaries to check for misspelled words.
5. list: This is an aspell action that tells the command to list the misspelled words found in the input.

In summary, the command reads the contents of a file specified by ${filename}, sends it to aspell along with a personal word list file specified by ${personal-word-list-pws}, and then aspell lists any misspelled words it finds in the input file.