Chapter 1, Interacting with the Environment, explores how your code can interact with the operating system environment. The use of command-line flags and arguments, consuming signals, and working with child processes are also covered.
Chapter 2, Strings and Things, goes through common operations on strings, from simple searching for substrings to formatting text to tabs.
Chapter 3, Dealing with Numbers, sheds light on basic conversions and number formatting options. Operations with large numbers and the correct use of plurals within output messages are covered.
Chapter 4, Once Upon a Time, puts the time package under the magnifying glass and covers formatting, arithmetics, and running code for given time period or after ...