Peter Passchier comment on Famous Awk One-Liners Explained, Part II: Text Conversion and Substitution

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Perl one-liners explained

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Peter Passchier Permalink

February 22, 2009, 11:23

One-liner 42 is not correct if the first line of a file is empty, because it will match the initial value of a. I came up with:
awk 'BEGIN {srand();a=rand()} a!=$0 {a=$0;print}'

(I didn't understand what the semicolon after a!=$0 does or means, so I removed it, and added a print action whenever the line isn't equal to the previous.)

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