Mark G. Sobell is President of Sobell Associates Inc., a consulting firm that specializes in UNIX and Linux training, support, and documentation. He has more than thirty years of experience working with UNIX and Linux systems and is the author of many best-selling books, including A Practical Guide to Linux® Commands, Editors, and Shell Programming, Third Edition, and A Practical Guide to Ubuntu Linux®, Third Edition, both from Prentice Hall.
