Join David D. Levine for an in-depth discussion in this video Using built-in variables, part of AWK Essential Training.
…Although it's simpler than other languages like Perl and Python, Awk is a…fully fledged programming language, and it has…a full complement of variables and operators.…Although this course assumes you've had some…exposure to basic programming language concepts, right now…I'm going to give you a brief introduction…to these concepts as they're implemented in Awk.…In the previous chapter, we looked at the variables FS,…RS, OFS, and ORS, which control field and record separators.…These are examples of built-in variables, which are…defined by Awk rather than by the user.…
You've also seen the variable NF, whose value is the number of fields on the line.…Related to NF is the special variable NR, whose value is the…record number or line number of the record that is currently being examined.…So instead of the number of fields, we'll print the record number.…Both of these variables can be used in patterns as well as actions.…For example, if we say, use the pattern NF is equal to six, it…prints only those lines in the input that have exactly six fields.…
Author
David D. Levine
Released
5/21/2014In this course, award-winning author and teacher David D. Levine shows you how to use AWK to read and write data in a variety of formats, produce reports, and automate repetitive tasks. He reviews the nuts and bolts of the language, such as field separators, pattern matching, variables, operators, expressions, and control structures; functions available for manipulating data; and integration with other programs like Excel.
- Determine what AWK is.
- Recognize how to write an AWK program.
- Determine how to use AWK command-line flags.
- Identify how to specify field and record separators with variables.
- Distinguish how to change a CVS file to a tab-separated one.
- Break down how to work with operators and arrays.
- Discover how to format output.
- Interpret how to string data with functions.
Skill Level Intermediate
Duration
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Introduction
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Welcome59s
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1. What Is AWK?
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What is AWK?3m 11s
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2. AWK Command Line Basics
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Writing an AWK program2m 51s
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Using AWK command-line flags6m 18s
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3. Understanding Records and Fields
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4. Understanding Variables and Operators
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5. A Quick Introduction to Regular Expressions
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Regular expression basics5m 19s
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6. Using Control Structures
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Building control structures4m 14s
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Creating an HTML table4m 45s
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7. Formatting the Output
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8. Functions and Arrays
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Manipulating strings7m 28s
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Using associative arrays4m 55s
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9. Combining AWK with Other Tools
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Using pipes7m 6s
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Scripting with AWK4m 56s
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Challenge: Perform a join1m 13s
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Solution: Perform a join2m 55s
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Conclusion
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Goodbye1m 10s
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Video: Using built-in variables