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Comparing and Merging Files with GNU diff and patch
by David MacKenzie, Paul Eggert, and Richard Stallman
Paperback (6"x9"), 120 pages
ISBN 0954161750
RRP £12.95 ($19.95)

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1.2 Suppressing Differences in Blank and Tab Spacing

The -E and --ignore-tab-expansion options ignore the distinction between tabs and spaces on input. A tab is considered to be equivalent to the number of spaces to the next tab stop. diff assumes that tab stops are set every 8 print columns.

The -b and --ignore-space-change options are stronger. They ignore white space at line end, and consider all other sequences of one or more white space characters to be equivalent. With these options, diff considers the following two lines to be equivalent, where ‘$’ denotes the line end:

Here lyeth  muche rychnesse  in lytell space.   -- John Heywood$
Here lyeth muche rychnesse in lytell space. -- John Heywood   $

The -w and --ignore-all-space options are stronger still. They ignore difference even if one line has white space where the other line has none. White space characters include tab, newline, vertical tab, form feed, carriage return, and space; some locales may define additional characters to be white space. With these options, diff considers the following two lines to be equivalent, where ‘$’ denotes the line end and ‘^M’ denotes a carriage return:

Here lyeth  muche  rychnesse in lytell space.--  John Heywood$
 He relyeth much erychnes seinly tells pace.  --John Heywood ^M$
ISBN 0954161750Comparing and Merging Files with GNU diff and patchSee the print edition