Datasheet
Linux programmers, or UNIX programmers for that matter. In the course of the book, we’ll mention a
couple of the alternatives.
A vast range of programming languages are available for Linux systems, and many of them are free and
available on CD-ROM collections or from FTP archive sites on the Internet. Here’s a partial list of pro-
gramming languages available to the Linux programmer:
We show how you can use a Linux shell (
bash) to develop small- to medium-sized applications in
Chapter 2. For the rest of the book, we mainly concentrate on C. We direct our attention mostly toward
exploring the Linux programming interfaces from the perspective of the C programmer, and we assume
knowledge of the C programming language.
Linux Programs
Linux applications are represented by two special types of files: executables and scripts. Executable files
are programs that can be run directly by the computer; they correspond to Windows
.exe files. Scripts
are collections of instructions for another program, an interpreter, to follow. These correspond to
Windows
.bat or .cmd files, or interpreted BASIC programs.
Linux doesn’t require executables or scripts to have a specific filename or any extension whatsoever. File
system attributes, which we discuss in Chapter 2, are used to indicate that a file is a program that may
be run. In Linux, you can replace scripts with compiled programs (and vice versa) without affecting
other programs or the people who call them. In fact, at the user level, there is essentially no difference
between the two.
When you log in to a Linux system, you interact with a shell program (often
bash) that runs programs in
the same way that the Windows command prompt does. It finds the programs you ask for by name by
Ada C C++
Eiffel Forth Fortran
Icon Java JavaScript
Lisp Modula 2 Modula 3
Oberon Objective C Pascal
Perl PostScript Prolog
Python Ruby Smalltalk
PHP Tcl/Tk Bourne Shell
In fact, the first version of UNIX was written in PDP 7 assembler language in 1969. C
was conceived by Dennis Ritchie around that time, and in 1973 he and Ken Thompson
rewrote essentially the entire UNIX kernel in C, quite a feat in the days when system
software was written in assembly language.
5
Chapter 1: Getting Started
47627c01.qxd:WroxPro 9/28/07 8:56 PM Page 5