Beginning Portable Shell Scripting: From Novice to Professional

CHAPTER 1Introduction to Shell Scripting

The UNIX command-line interface has been criticized for complexity and a steep learning curve, but no one disputes that it is one of the most flexible and programmable user interfaces ever developed. The core of the UNIX command-line interface is the shell, a program that interprets and executes user commands. The shell can take commands from a keyboard or stored in files; the syntax and commands are the same either way. A file containing shell commands is called a shell script. Many systems offer shells that are arguably programmable; the UNIX shell environment is actually good at it. As a result, thousands upon thousands of programs have been implemented as shell scripts. This book treats the shell ...