Introducing UNIX and Linux

Advanced shell programming

Overview
Sending and trapping signals
      Signal names
Functions
Aliases
The 'exec' mechanism
The 'eval' mechanism
Sending data across networks
      Sending printable characters
      Splitting files
Makefiles
Safe programming
Setting up a terminal
More on files
Miscellaneous utilities
Summary
Exercises

Overview

This chapter covers

trapping signals;
shell functions;
the 'exec' and 'eval' mechanisms;
mailing files which are not text files; and
other POSIX utilities not discussed elsewhere in this book.

In this chapter we examine briefly those aspects of shells that are not required later in this book, and which may be considered as 'advanced' in comparison with those topics already covered. The other chapters in the book will enable you to use the shell quite adequately, and the contents of this chapter are by no means necessary for you to be a competent shell programmer. However, even if you do not at this stage make use of the facilities discussed in this chapter, knowledge of their existence is important should you in the future decide to study shell programming in greater detail. Also, if you read shell scripts written by other people, and if you encounter unfamiliar utilities, you will at least recognise the facilities they may use.