Get the output of the `ls` command, parse it with the `grep` command to filter for files without a `.txt` extension, and write the output to a file called `filtered_files.txt`, check the example below:
Here, `command1` is the command that generates the output you want to parse, and `command2` is the command that parses the output. The output of `command2` will be redirected to the file `output_file` using the `>` operator.