Yolinux.com

diff manpage

Search topic Section
Get manual page for the search topic
List all commands matching the search topic
List all topics in the manpage index

DIFF(1)				   GNU Tools			       DIFF(1)



NAME
       diff - find differences between two files

SYNOPSIS
       diff [options] from-file to-file

DESCRIPTION
       In the simplest case, diff compares the contents of the two files from-
       file and to-file.  A file name of - stands for text read from the stan-
       dard  input.   As  a special case, diff - - compares a copy of standard
       input to itself.

       If from-file is a directory and to-file is not, diff compares the  file
       in  from-file  whose file name is that of to-file, and vice versa.  The
       non-directory file must not be -.

       If both from-file and to-file are  directories,	diff  compares	corre-
       sponding files in both directories, in alphabetical order; this compar-
       ison is not recursive unless the -r or  --recursive  option  is	given.
       diff  never compares the actual contents of a directory as if it were a
       file.  The file that is fully specified	may  not  be  standard	input,
       because	standard  input	 is nameless and the notion of ''file with the
       same name'' does not apply.

       diff options begin with -, so normally from-file and  to-file  may  not
       begin  with -.  However, -- as an argument by itself treats the remain-
       ing arguments as file names even if they begin with -.

   Options
       Below is a summary of all of the options that GNU diff  accepts.	  Most
       options have two equivalent names, one of which is a single letter pre-
       ceded by -, and the other of which is a long name preceded by --.  Mul-
       tiple  single letter options (unless they take an argument) can be com-
       bined into a single command line word: -ac  is  equivalent  to  -a  -c.
       Long  named  options  can  be abbreviated to any unique prefix of their
       name.  Brackets ([ and ]) indicate that an  option  takes  an  optional
       argument.

       -lines Show  lines (an integer) lines of context.  This option does not
	      specify an output format by itself; it has no effect  unless  it
	      is combined with -c or -u.  This option is obsolete.  For proper
	      operation, patch typically needs at least two lines of  context.

       -a     Treat  all  files as text and compare them line-by-line, even if
	      they do not seem to be text.

       -b     Ignore changes in amount of white space.

       -B     Ignore changes that just insert or delete blank lines.

       --brief
	      Report only whether the files differ, not	 the  details  of  the
	      differences.

       -c     Use the context output format.

       -C lines
       --context[=lines]
	      Use  the context output format, showing lines (an integer) lines
	      of context, or three if lines is not given.  For	proper	opera-
	      tion, patch typically needs at least two lines of context.

       --changed-group-format=format
	      Use  format  to  output  a line group containing differing lines
	      from both files in if-then-else format.

       -d     Change the algorithm to perhaps find a smaller set  of  changes.
	      This makes diff slower (sometimes much slower).

       -D name
	      Make  merged if-then-else format output, conditional on the pre-
	      processor macro name.

       -e
       --ed   Make output that is a valid ed script.

       --exclude=pattern
	      When comparing  directories,  ignore  files  and	subdirectories
	      whose basenames match pattern.

       --exclude-from=file
	      When  comparing  directories,  ignore  files  and subdirectories
	      whose basenames match any pattern contained in file.

       --expand-tabs
	      Expand tabs to spaces in the output, to preserve	the  alignment
	      of tabs in the input files.

       -f     Make output that looks vaguely like an ed script but has changes
	      in the order they appear in the file.

       -F regexp
	      In context and unified format, for  each	hunk  of  differences,
	      show some of the last preceding line that matches regexp.

       --forward-ed
	      Make output that looks vaguely like an ed script but has changes
	      in the order they appear in the file.

       -h     This option currently has no effect; it is present for Unix com-
	      patibility.

       -H     Use heuristics to speed handling of large files that have numer-
	      ous scattered small changes.

       --horizon-lines=lines
	      Do not discard the last lines lines of the common prefix and the
	      first lines lines of the common suffix.

       -i     Ignore  changes  in case; consider upper- and lower-case letters
	      equivalent.

       -I regexp
	      Ignore changes that just insert or delete lines that match  reg-
	      exp.

       --ifdef=name
	      Make  merged if-then-else format output, conditional on the pre-
	      processor macro name.

       --ignore-all-space
	      Ignore white space when comparing lines.

       --ignore-blank-lines
	      Ignore changes that just insert or delete blank lines.

       --ignore-case
	      Ignore changes in case; consider upper- and lower-case to be the
	      same.

       --ignore-matching-lines=regexp
	      Ignore  changes that just insert or delete lines that match reg-
	      exp.

       --ignore-space-change
	      Ignore changes in amount of white space.

       --initial-tab
	      Output a tab rather than a space before the text of  a  line  in
	      normal  or context format.  This causes the alignment of tabs in
	      the line to look normal.

       -l     Pass the output through pr to paginate it.

       -L label
       --label=label
	      Use label instead of the file name in  the  context  format  and
	      unified format headers.

       --left-column
	      Print  only  the left column of two common lines in side by side
	      format.

       --line-format=format
	      Use format to output all input lines in in-then-else format.

       --minimal
	      Change the algorithm to perhaps find a smaller set  of  changes.
	      This makes diff slower (sometimes much slower).

       -n     Output RCS-format diffs; like -f except that each command speci-
	      fies the number of lines affected.

       -N
       --new-file
	      In directory comparison, if a file is found in only  one	direc-
	      tory, treat it as present but empty in the other directory.

       --new-group-format=format
	      Use format to output a group of lines taken from just the second
	      file in if-then-else format.

       --new-line-format=format
	      Use format to output a line taken from just the second  file  in
	      if-then-else format.

       --old-group-format=format
	      Use  format to output a group of lines taken from just the first
	      file in if-then-else format.

       --old-line-format=format
	      Use format to output a line taken from just the  first  file  in
	      if-then-else format.

       -p     Show which C function each change is in.

       -P     When comparing directories, if a file appears only in the second
	      directory of the two, treat it  as  present  but	empty  in  the
	      other.

       --paginate
	      Pass the output through pr to paginate it.

       -q     Report  only  whether  the  files differ, not the details of the
	      differences.

       -r     When comparing directories, recursively compare any  subdirecto-
	      ries found.

       --rcs  Output RCS-format diffs; like -f except that each command speci-
	      fies the number of lines affected.

       --recursive
	      When comparing directories, recursively compare any  subdirecto-
	      ries found.

       --report-identical-files
       -s     Report when two files are the same.

       -S file
	      When  comparing  directories, start with the file file.  This is
	      used for resuming an aborted comparison.

       --from-file=file
	      Compare file to all operands.  file can be a directory.

       --to-file=file
	      Compare all operands to file. file can be a directory.

       --sdiff-merge-assist
	      Print extra information to help sdiff.  sdiff uses  this	option
	      when it runs diff.  This option is not intended for users to use
	      directly.

       --show-c-function
	      Show which C function each change is in.

       --show-function-line=regexp
	      In context and unified format, for  each	hunk  of  differences,
	      show some of the last preceding line that matches regexp.

       --side-by-side
	      Use the side by side output format.

       --speed-large-files
	      Use heuristics to speed handling of large files that have numer-
	      ous scattered small changes.

       --starting-file=file
	      When comparing directories, start with the file file.   This  is
	      used for resuming an aborted comparison.

       --suppress-common-lines
	      Do not print common lines in side by side format.

       -t     Expand  tabs  to spaces in the output, to preserve the alignment
	      of tabs in the input files.

       -T     Output a tab rather than a space before the text of  a  line  in
	      normal  or context format.  This causes the alignment of tabs in
	      the line to look normal.

       --text Treat all files as text and compare them line-by-line,  even  if
	      they do not appear to be text.

       -u     Use the unified output format.

       --unchanged-group-format=format
	      Use  format  to  output  a group of common lines taken from both
	      files in if-then-else format.

       --unchanged-line-format=format
	      Use format to output a line common to both files in if-then-else
	      format.

       --unidirectional-new-file
	      When comparing directories, if a file appears only in the second
	      directory of the two, treat it  as  present  but	empty  in  the
	      other.

       -U lines
       --unified[=lines]
	      Use  the unified output format, showing lines (an integer) lines
	      of context, or three if lines is not given.  For	proper	opera-
	      tion, patch typically needs at least two lines of context.

       -v
       --version
	      Output the version number of diff.

       -w     Ignore white space when comparing lines.

       -W columns
       --width=columns
	      Use an output width of columns in side by side format.

       -x pattern
	      When  comparing  directories,  ignore  files  and subdirectories
	      whose basenames match pattern.

       -X file
	      When comparing  directories,  ignore  files  and	subdirectories
	      whose basenames match any pattern contained in file.

       -y     Use the side by side output format.

SEE ALSO
       cmp(1), comm(1), diff3(1), ed(1), patch(1), pr(1), sdiff(1).

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



GNU Tools			   22sep1993			       DIFF(1)
YoLinux.com Home Page
YoLinux Tutorial Index
Privacy Policy | Advertise with us | Feedback Form |
Unauthorized copying or redistribution prohibited.
    Bookmark and Share