Linux in a Nutshell, Fifth Edition

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Chapter 3: Linux Commands

This is the Title of the Book, eMatter Edition

Copyright © 2006 O’Reilly & Associates, Inc. All rights reserved.

diff

diff [options] [diroptions] file1 file2

Compare two text files. diff reports lines that differ between file1

and file2. Output consists of lines of context from each file, with

file1 text flagged by a < symbol and file2 text by a > symbol.

Context lines are preceded by the ed command (a, c,ord) that

would be used to convert file1 to file2. If one of the files is -, stan-

dard input is read. If one of the files is a directory, diff locates the

filename in that directory corresponding to the other argument (e.g.,

diff my_dir junk is the same as diff my_dir/junk junk). If both argu-

ments are directories, diff reports lines that differ between all pairs

of files having equivalent names (e.g., olddir/program and newdir/

program); in addition, diff lists filenames unique to one directory, as

well as subdirectories common to both. See also cmp.

Options

-a, --text

Treat all files as text files. Useful for checking to see if binary

files are identical.

-b, --ignore-space-change

Ignore repeating blanks and end-of-line blanks; treat succes-

sive blanks as one.

-B, --ignore-blank-lines

Ignore blank lines in files.

-c Context diff: print 3 lines surrounding each changed line.

-C n, --context[=n]

Context diff: print n lines surrounding each changed line. The

default context ...