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Ruby's CSV module can be handy:

    ruby -rcsv -ne 'CSV($<).each { |r| puts r[0] }' 
I like the seen example the dude has:

    '!seen[$1]++'



As someone who's new to programming and doesn't know Ruby at all, can you (or someone) please explain how it works, what it does, and how would someone use it?

I find it beautiful, tho :)


    -rcvs
Load the (built-in) CSV module in Ruby.

    -e
Eval the following string as Ruby code.

    CSV($<)
Create CSV parser with standard input `$<` as the source.

    .each 
Run the code in the block that follows for each row (automatically skips the CSV header):

    { |r| puts r[0] }
For a row, print the first/0th element. Can be simplified in recent Ruby:

    { puts _1[0] }


Thank you so much! This got me looking at the Ruby documentation about blocks. Very cool feature!


I didn’t know you could do that in ruby but its pretty cool




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