diff Man page

Resume Wikipedia de Diff

diff est une commande Unix qui permet de comparer deux fichiers et d’en afficher les différences.
Son utilisation typique consiste à calculer les changements entre une version d’un fichier et une version plus ancienne du même fichier. Diff affiche les changements ligne par ligne pour un fichier texte, mais ne gère pas toujours de façon conviviale la différence de Byte Order Mark. Les implémentations modernes prennent également en compte les fichiers binaires. La sortie est appelée un “diff”, un patch, ou une rustine puisque la sortie permet de transformer le premier fichier binaire en le second par le programme Unix patch.

DIFF(1) User Commands DIFF(1)


diff – compare files line by line




Compare FILES line by line.

Mandatory arguments to long options are mandatory for short options

output a normal diff (the default)

-q, –brief
report only when files differ

-s, –report-identical-files
report when two files are the same

-c, -C NUM, –context[=NUM] output NUM (default 3) lines of copied context

-u, -U NUM, –unified[=NUM] output NUM (default 3) lines of unified context

-e, –ed
output an ed script

-n, –rcs
output an RCS format diff

-y, –side-by-side
output in two columns

-W, –width=NUM
output at most NUM (default 130) print columns

output only the left column of common lines

do not output common lines

-p, –show-c-function
show which C function each change is in

-F, –show-function-line=RE
show the most recent line matching RE

–label LABEL
use LABEL instead of file name (can be repeated)

-t, –expand-tabs
expand tabs to spaces in output

-T, –initial-tab
make tabs line up by prepending a tab

tab stops every NUM (default 8) print columns

suppress space or tab before empty output lines

-l, –paginate
pass output through `pr’ to paginate it

-r, –recursive
recursively compare any subdirectories found

-N, –new-file
treat absent files as empty

treat absent first files as empty

ignore case when comparing file names

consider case when comparing file names

-x, –exclude=PAT
exclude files that match PAT

-X, –exclude-from=FILE
exclude files that match any pattern in FILE

-S, –starting-file=FILE
start with FILE when comparing directories

compare FILE1 to all operands; FILE1 can be a directory

compare all operands to FILE2; FILE2 can be a directory

-i, –ignore-case
ignore case differences in file contents

-E, –ignore-tab-expansion
ignore changes due to tab expansion

-Z, –ignore-trailing-space
ignore white space at line end

-b, –ignore-space-change
ignore changes in the amount of white space

-w, –ignore-all-space
ignore all white space

-B, –ignore-blank-lines
ignore changes whose lines are all blank

-I, –ignore-matching-lines=RE
ignore changes whose lines all match RE

-a, –text
treat all files as text

strip trailing carriage return on input

-D, –ifdef=


output merged file with `#ifdef NAME’ diffs

format GTYPE input groups with GFMT

format all input lines with LFMT

format LTYPE input lines with LFMT

These format options provide fine-grained control over the out‐

of diff, generalizing -D/–ifdef.

LTYPE is `old’, `new’, or `unchanged’.
GTYPE is LTYPE or `changed’.

GFMT (only) may contain:

%< lines from FILE1 %> lines from FILE2

%= lines common to FILE1 and FILE2

printf-style spec for LETTER

LETTERs are as follows for new group, lower case for old group:

F first line number

L last line number

N number of lines = L-F+1

E F-1

M L+1

if A equals B then T else E

LFMT (only) may contain:

%L contents of line

%l contents of line, excluding any trailing newline

printf-style spec for input line number

Both GFMT and LFMT may contain:

%% %

%c’C’ the single character C

the character with octal code OOO

C the character C (other characters represent themselves)

-d, –minimal
try hard to find a smaller set of changes

keep NUM lines of the common prefix and suffix

assume large files and many scattered small changes

–help display this help and exit

-v, –version
output version information and exit

FILES are `FILE1 FILE2′ or `DIR1 DIR2′ or `DIR FILE…’ or `FILE…
DIR’. If –from-file or –to-file is given, there are no restrictions
on FILE(s). If a FILE is `-‘, read standard input. Exit status is 0
if inputs are the same, 1 if different, 2 if trouble.


Written by Paul Eggert, Mike Haertel, David Hayes, Richard Stallman,
and Len Tower.


Report bugs to: bug-diffutils@gnu.org
GNU diffutils home page:
General help using GNU software:


Copyright © 2011 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.


wdiff, cmp, diff3, sdiff, patch

The full documentation for diff is maintained as a Texinfo manual. If
the info and diff programs are properly installed at your site, the

info diff

should give you access to the complete manual.

diffutils 3.3 March 2013 DIFF(1)