Welcome to refcards.com. Here you will find a collection of quick reference cards focused mainly on Free and Open Source Software.
Some of the cards are hosted on this site; others are located externally. For external sites the links generally go to pages about the cards rather than directly to the cards. Most authors prefer this. Local information about externally hosted cards is indicated with the [information] icon. Most of the cards are in PDF format.
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Perl
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