10.4. Calling the OS

Ruby supports a number of global functions for interacting with the operating system to execute programs, fork new processes, handle signals, and so on. Ruby was initially developed for Unix-like operating systems, and many of these OS-related functions reflect that heritage. By their very nature, these functions are less portable than most others, and some may not be implemented at all on Windows and other non-Unix platforms. The subsections that follow describe some of the most commonly used of the OS-dependent functions. Functions, such a syscall, that are particularly low-level or platform-dependent are not covered here.

10.4.1. Invoking OS Commands

The Kernel.` method expects a single string argument representing an OS shell command. It starts a subshell and passes the specified text to it. The return value is the text printed to standard output. This method is typically invoked using special syntax; it is invoked on string literals surrounded by backquotes or on string literals delimited with %x (see Section 3.2.1.6). For example: