diffstat - make histogram from diff-output


       diffstat [options] [file-specifications]


       This  program  reads the output of diff and displays a histogram of the
       insertions, deletions, and modifications per-file.  Diffstat is a  pro-
       gram that is useful for reviewing large, complex patch files.  It reads
       from one or more input files which contain output from diff,  producing
       a histogram of the total lines changed for each file referenced.

       If  the input filename ends with ".bz2", ".gz", ".lzma", ".xz", ".z" or
       ".Z", diffstat will read the uncompressed data via a pipe from the cor-
       responding  program.  It also can infer the compression type from files
       piped via the standard input.

       Diffstat recognizes the most popular types of output from diff:

                 preferred by the patch utility.

                 best for readability, but not very compact.

                 not good for much, but simple to generate.

       Diffstat detects the lines that are output by diff to tell which  files
       are  compared,  and  then  counts  the markers in the first column that
       denote the type of change (insertion, deletion or modification).  These
       are shown in the histogram as "+", "-" and "!" characters.

       If no filename is given on the command line, diffstat reads the differ-
       ences from the standard input.


       -b     ignore lines matching "Binary files XXX and YYY differ"  in  the

       -c     prefix  each  line  of output with "#", making it a comment-line
              for shell scripts.

       -C     add SGR color escape sequences to highlight the histogram.

       -D destination
              specify a directory containing files which can be referred to as
              the result of applying the differences.  diffstat will count the
              lines in the corresponding files (after adjusting the  names  by
              the -p option) to obtain the total number of lines in each file.

              The  remainder, after subtracting modified and deleted lines, is
              shown as "unchanged lines".

       -d     The debug prints a lot of information.  It is normally compiled-
              in, but can be suppressed.

       -e file
              redirect standard error to file.

       -E     strip  out ANSI escape sequences on each line before parsing the
              differences.  This allows diffstat to be used with colordiff.

       -f format
              specify the format of the histogram.

              0  for concise, which shows only the value  and  a  single  his-
                 togram code for each of insert (+), delete (-) or modify (!)

              1  for normal output,

              2  to fill in the histogram with dots,

              4  to print each value with the histogram.

              Any  nonzero  value  gives a histogram.  The dots and individual
              values can be combined, e.g., -f6 gives both.

       -h     prints the usage message and exits.

       -k     suppress the merging of filenames in the report.

       -K     attempt to improve the annotation of "only" files by looking for
              a  match in the resulting set of files and inferring whether the
              file was added or removed.

              This does not currently work  in  combination  with  -R  because
              diffstat maintains only the resulting set of files.

       -l     lists only the filenames.  No histogram is generated.

       -m     merge  insert/delete  counts from each "chunk" of the patch file
              to approximate a count of the modified lines.

       -n number
              specify the minimum width used for filenames.   If  you  do  not
              specify  this, diffstat uses the length of the longest filename,
              after stripping common prefixes.

       -N number
              specify the maximum width used for filenames.  Names longer than
              this  limit  are  truncated  on the left.  If you do not specify
              this, diffstat next checks the -n option.

       -o file
              redirect standard output to file.

       -p number
              override the logic that strips common pathnames, simulating  the
              patch "-p" option.

              If  you  do  not give a -p option, diffstat examines the differ-
              ences and strips the common prefix from the pathnames.  This  is
              not what patch does.

       -q     suppress the "0 files changed" message for empty diffs.

       -r  code
              provides  optional  rounding  of  the  data  shown in histogram,
              rather than truncating with error adjustments.

              0  is the default.  No rounding is  performed,  but  accumulated
                 errors are added to following columns.

              1  rounds the data

              2  rounds  the  data and adjusts the histogram to ensure that it
                 displays something if there are any differences even if those
                 would normally be rounded to zero.

       -R     Assume patch was created with old and new files swapped.

       -s     show only the summary line, e.g., number of insertions and dele-

       -S source
              this is like the -D option, but specifies a location  where  the
              original files (before applying differences) can be found.

       -t     overrides  the  histogram,  generates  output of comma separated
              values for the number of changed lines found in the  differences
              for each file: inserted, deleted and modified.

              If  -S  or  -D  options are given, the number of unchanged lines
              precedes the number of changes.

       -T     prints the numbers that the -t option would  show,  between  the
              pathname and histogram.

              The  width of the number of changes is determined by the largest
              value (but at least 3).  The width given in  the  -w  option  is
              separate from the width of these numbers.

       -u     suppress the sorting of filenames in the report.

       -v     show  progress,  e.g.,  if  the  output is redirected to a file,
              write progress messages to the standard error.

       -V     prints the current version number and exits.

       -w number
              specify the maximum width of the histogram.  The histogram  will
              never be shorter than 10 columns, just in case the filenames get
              too large.

              The default is 80 columns, unless the output is to  a  terminal.
              In that case, the default width is the terminal's width.


       Diffstat runs in a POSIX environment.

       You can override the compiled-in paths of programs used for decompress-
       ing input files by setting environment variables corresponding to their


       However, diffstat assumes that the resulting program uses the same com-
       mand-line options, e.g., "-c" to decompress to the standard output.


       Diffstat is a single binary module, which uses no auxiliary files.


       Diffstat makes a lot of assumptions about the format of diff's output.

       There is no way to obtain a filename from the standard diff between two
       files with no options.  Context diffs work, as well as unified diffs.

       There's  no  easy  way  to  determine the degree of overlap between the
       "before" and "after"  displays  of  modified  lines.   diffstat  simply
       counts the number of inserted and deleted lines to approximate modified
       lines for the -m option.


       diff(1), patch(1).


       Thomas Dickey <>.