DIFFSTAT(1) DIFFSTAT(1)
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
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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.
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-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.
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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
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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>.
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