Overview This book delivers what the title states: It describes the 101 most important UNIX and Linux commands and system calls. The book bridges the gap between on-line tutorials and manual pages on one hand, and books of 1,000 pages or more that explore the nuances of many shell commands in exhaustive detail. While most of these sources provide excellent information, they do not really solve the plight of the novice user, nor do they fully answer the questions that more experienced, and even expert, users often have. Much of the complexity of UNIX and Linux, and much of the difficulty faced by users is caused by the extremely large and rich set of shell commands, many of which have a very large set of allowable options that, while useful in certain circumstances, often provide more frustration than help because of their complexity. Many UNIX and Linux system calls are also complex, and have interactions that can be rather difficult for many programmers.