The awesome linux bash

I'm a big fan of unix and bash, the idea of having tons of small tools that can be combined to achieve complex result is really neat.
Recently I had to download a big list of files from amazon s3. I ended up doing:

cat <(cat list_of_file.txt) <(ls downloaded_files) | sort | uniq -u | xargs -I {} -P6 aws s3 cp s3://bucket_name/sub/directory/full/of/files/{} ./downloaded_files

Some explanation (for my future self)

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