- By using ((:
#!/bin/bash
num=$(( 25 - 8 ))
echo $num
- The problem is with the space in the filename. To fix it, put the filename between quotes:
$ rm "my file"
- There is no dollar sign before the parentheses:
#!/bin/bash
a=$(( 8 + 4 ))
echo $a
- Title Page
- Copyright and Credits
- Packt Upsell
- Contributors
- Preface
- The What and Why of Scripting with Bash
- Creating Interactive Scripts
- Technical requirements
- Using echo with options
- Basic script using read
- Script comments
- Enhancing scripts with read prompts
- Limiting the number of entered characters
- Controlling the visibility of the entered text
- Passing options
- Try to be standard
- Enhancing learning with simple scripts
- Summary
- Questions
- Further reading
- Conditions Attached
- Technical requirements
- Simple decision paths using command-line lists
- Verifying user input with lists
- Using the test shell built-in
- Creating conditional statements using if
- Extending if with else
- Test command with the if command
- More conditions with elif
- Using case statements
- Recipe – building a frontend with grep
- Summary
- Questions
- Further reading
- Creating Code Snippets
- Alternative Syntax
- Iterating with Loops
- Creating Building Blocks with Functions
- Introducing the Stream Editor
- Automating Apache Virtual Hosts
- AWK Fundamentals
- Regular Expressions
- Summarizing Logs with AWK
- A Better lastlog with AWK
- Using Python as a Bash Scripting Alternative
- Assessments
- Other Books You May Enjoy
Chapter 5
-
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