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Regular expressions should be familiar as they are used in many UNIX commands with grep being the best known
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% grep pattern file; # Print each line of a file containing pattern
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Consider the simple pattern /Fox/. We can write the PERL version of grep as follows:
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$line = 0;
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while (<>) {
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if ( /Fox/ ) {
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}
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$line++;
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}
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Another familiar operator is s in sed (the batch or stream line editor) where
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s/Pat1/Pat2/; # substitutes Pat1 by Pat2 in each line
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We'll have more to say about the s operator later
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