Hello World and Ruby Syntax

Every Ruby program starts somewhere, and the traditional first program is simply printing text to the screen. Beyond that trivial example, understanding Ruby's syntax conventions early pays off: how statements are terminated, how blocks are delimited, how method calls look with and without parentheses, and how files are structured. Ruby's syntax is notably permissive compared to many languages, which is part of what makes it feel conversational, but that same permissiveness means style conventions matter more for keeping code readable.

A Ruby program is simply a .rb file containing Ruby code, executed by the ruby interpreter. There is no required main function or class wrapper; top-level code executes sequentially from the first line. The puts method prints its argument followed by a newline, while print omits the trailing newline and p prints the argument's inspect representation, useful for debugging because it clearly shows strings, nil, and special characters.

Ruby statements are typically one per line and do not require a terminating semicolon, though semicolons can separate multiple statements on one line. Blocks of code—method bodies, class definitions, conditionals, loops—are closed with the keyword end rather than braces, except for single-line blocks which use { }. Method calls often omit parentheses when unambiguous (puts "hi" is equivalent to puts("hi")), a stylistic choice embraced throughout idiomatic Ruby, though parentheses are recommended when passing multiple arguments or nesting calls for clarity.