Awk's "two" explanations

As a powerful text processing tool, awk is essential for our daily work.

Basic syntax for awk:

awk [option parameter] ' script ' Var=value file or

awk [option parameter]-F scriptfile var=value file

Mans awk

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Basic parameter Description :

-F: Specifies the file separation domain,

-V Var=value or--asign var=value: Assigns a user-defined variable

-MF nnn AND-MR nnn: It's no use at the moment. You can do it yourself Google

-W compact,-w Traditional: Running awk in compatibility mode, in fact awk and gawk are almost exactly the same.

-W copyleft,-w Copyright: Print short, copyrighted information.

-W help,-w usage: Prints the help information for awk.

-W Lint or--lint: Prints structural warnings that cannot be ported to traditional UNIX platforms.

-W POSIX: Turns on compatibility mode with limited, unrecognized:/x, function keyword, func, swap sequence, and when FS is a space, the new row is used as a domain delimiter; flush is not valid.

-W Re-interval: Allows the use of interval regular expressions.

-W Source Program-text: Use Program-text as the source code and can be used in combination with the-f command.

-W version: Prints the bug version information.

Usage: Here I have a text file Test.txt, which reads as follows

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awk defaults to a space or tab as the delimiter.

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Try to, as a delimiter.

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The above command is equivalent to: awk ' BEGIN {fs= ', '} {print $1,$4} ' Test.txt ' This is the use of built-in variables '

Use multiple separators, divide the spaces first, and then use "," to split the split results.

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awk setting variable "can specify multiple variables"

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awk sequence number nr, which matches the line number of the text.

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AWK Specifies the output separator symbol.

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Regular use

Match $ contains "th", and print $2,$4, "~" symbol is the matching regular, representing the pattern start,//is to match the pattern

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Output rows containing "is"

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How to ignore uppercase and lowercase

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Take the anti-operation, a bit like the way grep is expressed.

Ignores case, matching the first column is not a/th/row.

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Another way of writing

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awk Script

awk script Two keywords: BEGIN and end[note is uppercase]

Begin{represents the statement before execution}

End{represents the statement after execution}

Where you can add a Process control statement [if while for break continue, etc.]

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Cond

Awk's "two" explanations