Provided by: diffstat_1.63-1_amd64 
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.
SEE ALSO
diff(1), patch(1).
AUTHOR
Thomas Dickey <dickey@invisible-island.net>.
DIFFSTAT(1)