Provided by: diffstat_1.61-1_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, .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.
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)