Single characters, symbolic expressions, and command-line switches are always
shown in constant-width font. For instance, the o option illustrates a single character,
the rule $- illustrates a symbolic expression, and -d illustrates a commandline
switch.
* The versions jump from 5 to 8 because the managers of the BSD 4.4 Unix distribution wanted all software
to be released as version 8. Prior to that decision, the new BSD sendmail was designated Version 6. V6 survived
only the alpha and beta releases before being bumped to V8.
This is the Title of the Book, eMatter Edition
Copyright ?© 2007 O??™Reilly & Associates, Inc. All rights reserved.
Preface | xxi
Constant Bold
Used in examples to show commands or some other text that is to be typed literally
by the user. For example, the phrase cat /var/run/sendmail.pid means the
user should type ???cat /var/run/sendmail.pid??? exactly as it appears in the text or
example.
Constant Italic
Used in examples to show variables for which a context-specific substitution
should be or will be made. In the string Snum, for example, num will be a userassigned
integer.
% Indicates a user shell.
# Indicates a root shell.
Using Code Examples
This book is here to help you get your job done. In general, you may use the code in
this book in your programs and documentation. You do not need to contact us for
permission unless you??™re reproducing a significant portion of the code.
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