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", ".zst",
 ".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
 DIFFSTAT_ZSTD_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>.