Using 'diff' (or anything else) to get character-level diff between text files

user_126574 0
Viewed 70562

I'd like to use 'diff' to get a both line difference between and character difference. For example, consider:

File 1

abcde
abc
abcccd

File 2

abcde
ab
abccc

Using diff -u I get:

@@ -1,3 +1,3 @@
 abcde
-abc
-abcccd
\ No newline at end of file
+ab
+abccc
\ No newline at end of file

However, it only shows me that were changes in these lines. What I'd like to see is something like:

@@ -1,3 +1,3 @@
 abcde
-ab<ins>c</ins>
-abccc<ins>d</ins>
\ No newline at end of file
+ab
+abccc
\ No newline at end of file

You get my drift.

Now, I know I can use other engines to mark/check the difference on a specific line. But I'd rather use one tool that does all of it.

diff command-line text
16 Answers

You can use:

diff -u f1 f2 |colordiff |diff-highlight

screenshot

colordiff is a Ubuntu package. You can install it using sudo apt-get install colordiff.

diff-highlight is from git (since version 2.9). It is located in /usr/share/doc/git/contrib/diff-highlight/diff-highlight. You can put it somewhere in your $PATH.

user_4257580

You can use the cmp command in Solaris:

cmp

Compare two files, and if they differ, tells the first byte and line number where they differ.

user_2296080 
cmp -l file1 file2 | wc

Worked well for me. The leftmost number of the result indicates the number of characters that differ.

user_16758750

Coloured, character-level diff ouput

Here's what you can do with the the below script and diff-highlight (which is part of git):

Coloured diff screenshot

#!/bin/sh -eu

# Use diff-highlight to show word-level differences

diff -U3 --minimal "$@" |
  sed 's/^-/\x1b[1;31m-/;s/^+/\x1b[1;32m+/;s/^@/\x1b[1;34m@/;s/$/\x1b[0m/' |
  diff-highlight

(Credit to @retracile's answer for the sed highlighting)

user_53534610

ccdiff is a convenient dedicated tool for the task. Here is what your example looks like with it:

ccdiff example output

By default, it highlights the differences in color, but it can be used in a console without color support too.

The package is included in the main repository of Debian:

ccdiff is a colored diff that also colors inside changed lines.

All command-line tools that show the difference between two files fall short in showing minor changes visuably useful. ccdiff tries to give the look and feel of diff --color or colordiff, but extending the display of colored output from colored deleted and added lines to colors for deleted and addedd characters within the changed lines.

user_141149870

Not a complete answer, but if cmp -l's output is not clear enough, you can use:

sed 's/\(.\)/\1\n/g' file1 > file1.vertical
sed 's/\(.\)/\1\n/g' file2 > file2.vertical
diff file1.vertical file2.vertical
user_42501500

Most of these answers mention using of diff-highlight, a Perl module. But I didn't want to figure out how to install a Perl module. So I made a few minor changes to it to be a self-contained Perl script.

You can install it using:

▶ curl -o /usr/local/bin/DiffHighlight.pl \
   https://raw.githubusercontent.com/alexharv074/scripts/master/DiffHighlight.pl

And the usage (if you have the Ubuntu colordiff mentioned in zhanxw's answer):

▶ diff -u f1 f2 | colordiff | DiffHighlight.pl

And the usage (if you don't):

▶ diff -u f1 f2 | DiffHighlight.pl
user_37870510

As one comment to main answer said you don't have to commit to use git diff:

git diff --word-diff=color --word-diff-regex=. file1 file2

enter image description here

green would be the character that is added by the second file.

red would be the character that is added by the first file.

user_15773430
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