The new (4th!) edition of the world famous book "Unix and Linux: A System Administrator's Guide" by recognized authorities in the field of system administration of UNIX and Linux systems contains accurate and complete information on almost all aspects, including memory management, design and network management, email, web hosting, scripting, software configuration management, performance analysis, Windows interfacing, virtualization, DNS, security, IT service provider management and much more. Presenting important facts clearly and simply, the authors accompany them with real-life examples. The reference book differs from previous editions in that it covers modern versions of UNIX and Linux systems - Solaris, HP-UX, AIX, Ubuntu Linux, openSUSE and Red Hat Enterprise Linux. The authors paid special attention to the administration of networks running UNIX and Linux systems. This publication, which appeared in the year that marks the 20th anniversary of the world bestseller on UNIX system administration, has become even better thanks to the description of common variants of the Linux system: Ubuntu, openSUSE and RHEL. System administration in the book is considered from a practical point of view. It is an invaluable reference for both new administrators and seasoned professionals. It details best practices and covers all aspects of system administration, including memory management, network design and management, email, web hosting, scripting, software configuration management, performance analysis, Windows interfacing, virtualization, DNS, security. , IT service provider management and much more. This book reflects the current versions of the following operating systems: Ubuntu Linux open SUSE Linux Red Hat Enterprise Linux Oracle America SolarisTM (formerly Sun Solaris) HP HP-UX IBM AIX The book will be extremely useful to all system administrators, as well as users of UNIX systems and Linux, students, teachers and network technology specialists.