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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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12 Invoking cmp

The cmp command compares two files, and if they differ, tells the first byte and line number where they differ. Bytes and lines are numbered starting with 1. The arguments of cmp are as follows:

cmp options... from-file [to-file [from-skip [to-skip]]]

The file name ‘-’ is always the standard input. cmp also uses the standard input if one file name is omitted. The from-skip and to-skip operands specify how many bytes to ignore at the start of each file; they are equivalent to the --ignore-initial=from-skip:to-skip option.

An exit status of 0 means no differences were found, 1 means some differences were found, and 2 means trouble.

ISBN 0954161750Comparing and Merging Files with GNU diff and patchSee the print edition