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WikiPedia: Câu lệnh shell http://freebookcentre.net/UnixCategory/Free-Unix-S... http://www.faqs.org/docs/air/tsshell.html https://developer.apple.com/mac/library/documentat... https://books.google.com/books?id=9vCoCwAAQBAJ&pg=... https://books.google.com/books?id=J5nKVVg5YHAC https://books.google.com/books?id=Mpi7DQAAQBAJ&pg=... https://books.google.com/books?id=jO-iKwPRX0QC&pg=... https://books.google.com/books?id=tK4oIcnngiUC&pg=... https://books.google.com/books?id=zZYLAAAAQBAJ https://www.linux.com/articles/34658