Readers who are KornShell programmers should still scan Chapter 28, KornShell Language Review, looking for the KornShell-93 New Feature symbol shown here. Some of these features are highly useful for graphics programming. Chapter 31, KornShell Command Reference, also uses this icon to highlight commands that are new or changed in KornShell-93. These chapters do not assume any prior X experience and should be absorbed carefully. If possible, a system with dtksh installed should be nearby so the reader can experiment with the example programs.
Nothing can substitute for hands-on experience when learning graphics programming.
A first-time X programmer can skip Part II on first reading. These chapters contain advanced material and sometimes assume the reader is X and C literate. These people usually know how to write shell scripts too, but they may not be used to thinking of the shell language as a powerful graphical programming language. They might need some refresher material on shell programming. They don't need tutorials on basic X terminology or concepts, but they do need to know how X Window functions were mapped into the dtksh language from the C language, and they need to know what features in X are not currently supported by dtksh.