Seeing The World As The Shell Sees It Prepared by Dr Reyes New York City College of Technology Expansion echo command that displays a line of text echo can be combined with wildcards ID: 776187
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Slide1
The Linux Command Line Chapter 7
Seeing The World As The Shell Sees It
Prepared by Dr. Reyes, New York City College of Technology
Slide2Expansion
echo – command that displays a line of textecho can be combined with wildcards
Slide3Pathname Expansions
Slide4Tilde Expansion
Slide5Arithmetic Expansion
Uses the form $((expression))Operators supported:
Slide6Examples
Slide7Brace Expansion
Used to create multiple text strings from a pattern containing braces.Examples:
Slide8Parameter Expansion
Given a variable, place a $ to retrieve its valueExample:
Slide9Double Quotes
Double quotes – when used all the special characters used by the shell lose their special meaning and are treated as ordinary characters with the exception of “$”, “\” (backslash), and “`” (backquote).Examples:
Slide10Single Quotes
Single quotes – used to suppress all expansionsExample double vs. single quotes
Slide11Escape Characters
Escape character – use the backslash “\” before “$”, “!”, “&”, “ ”, and other characters with special meaning.Other escape sequences