How to Use C on a Unix System

The C programming language is used extensively in Unix. Every Unix and Unix-based operating system comes with a C compiler installed by default. Since 1973, the Unix operating system has been written entirely in C. Using C allows you to interact with the Unix kernel with low level system calls as well as create high level programs. The same C program can also be compiled on many different systems, making it useful for cross platform applications.

Instructions

1. Create a text document that contains your program. For this example, use the well known "Hello World" program.

   #include <stdio.h>
   main()
   {
   printf ("Hello World!\n");
   }

2. Save the program with the .c extension. This program is named example.c

3. Open a terminal window. The terminal window will be found in the Utilities submenu on most Unix systems.

4. Change to the directory where you saved your program. cd MyProgs/

5. Issue the command "cc -o example example.c" to compile the program.
   The "-o" option tells the compiler to name the compiled program "example". Without it, the resulting program will be named "a.out".

6. Run the program by issuing the command: ./example

References

• Programming in C