NAME

       diffstat - make histogram from diff-output

SYNOPSIS

       diffstat [options] [file-specifications]

DESCRIPTION

       This  program  reads  the  output  of  diff  and  displays  a histogram of the insertions, deletions, and
       modifications per-file.  Diffstat is a program 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 corresponding 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:

          unified
                 preferred by the patch utility.

          context
                 best for readability, but not very compact.

          default
                 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 differences from the standard input.

OPTIONS

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

       -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 histogram 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 differences 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 deletions.

       -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.

ENVIRONMENT

       Diffstat runs in a POSIX environment.

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

              DIFFSTAT_BZCAT_PATH
              DIFFSTAT_BZIP2_PATH
              DIFFSTAT_COMPRESS_PATH
              DIFFSTAT_GZIP_PATH
              DIFFSTAT_LZCAT_PATH
              DIFFSTAT_PCAT_PATH
              DIFFSTAT_UNCOMPRESS_PATH
              DIFFSTAT_XZ_PATH
              DIFFSTAT_ZCAT_PATH

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

FILES

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

BUGS

       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.

AUTHORS

       Thomas Dickey <dickey@invisible-island.net>.

SEE ALSO

       diff(1), patch(1).

1.66                                               2024-01-28                                        DIFFSTAT(1)