Linux Application Development, Second Edition

Chapter 9. Linux System Environment

This chapter explains how to request system services, including low-level kernel facilities and higher-level library facilities.

The Process Environment

As described in more detail in Chapter 10, each running process has environment variables. Environment variables are name/value pairs, and a few of the variable names have meaning that is important to C programmers. (Many are used primarily for shell programming as quick alternatives to running programs that call library functions; those we do not describe here.)

EDITOR or VISUAL

EDITOR, or VISUAL if it is set, provides the user’s preference for which text editor to use to edit text files, if your program requires asking the user to edit a text file. The reason ...