Classic Shell Scripting

Conventions Used in This Book

We leave it as understood that, when you enter a shell command, you press Enter at the end. Enter is labeled Return on some keyboards.

Characters called Ctrl-X, where X is any letter, are entered by holding down the Ctrl (or Ctl, or Control) key and then pressing that letter. Although we give the letter in uppercase, you can press the letter without the Shift key.

Other special characters are newline (which is the same as Ctrl-J), Backspace (the same as Ctrl-H), Esc, Tab, and Del (sometimes labeled Delete or Rubout).

This book uses the following font conventions:

Italic

Italic is used in the text for emphasis, to highlight special terms the first time they are defined, for electronic mail addresses and Internet URLs, and in manual page citations. It is also used when discussing dummy parameters that should be replaced with an actual value, and to provide commentary in examples.

Constant Width

This is used when discussing Unix filenames, external and built-in commands, and command options. It is also used for variable names and shell keywords, options, and functions; for filename suffixes; and in examples to show the contents of files or the output from commands, as well as for command lines or sample input when they are within regular text. In short, anything related to computer usage is in this font.

Constant Width Bold

This is used in the text to distinguish regular expressions and shell wildcard patterns from the text to be matched. It is also used in examples ...