Diffutils

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Resources

Diffutils is a package that contains several utilities for identifying the differences in two different files.

Installation

USE flags

USE flags for sys-apps/diffutils Tools to make diffs and compare files

`nls`	Add Native Language Support (using gettext - GNU locale utilities)
`verify-sig`	Verify upstream signatures on distfiles

Data provided by the Gentoo Package Database · Last update: 2024-09-12 18:37 More information about USE flags

Emerge

root #emerge --ask sys-apps/diffutils

Usage

The two files used in the examples are:

FILE one

Hello, World!
Second Line
Gentoo Linux
Another Line

FILE two

Goodbye, World!
Second Line
Gentoo Linux
Different Line

cmp

cmp is used to compare two files byte by byte and reports the first byte difference.

Comparing two files

Finding where the first byte difference is similar to using diff:

user $cmp one two

one two differ: byte 1, line 1

To print the bytes that differ, use -b:

user $cmp one two

one two differ: byte 1, line 1 is 110 H 107 G

diff

diff compares two files line by line

Basic comparisons

The most basic way to check the differences in two files is by using diff.

user $diff one two

1c1
< Hello, World!
---
> Goodbye, World!
4c4
< Another Line
---
> Different Line

What this says is the file on the left (one) has "Hello, World!" while the file on the right (two) has "Goodbye, World".

Columns

To show the differences in column format to compare side-by-side, use the -y argument.

user $diff -y one two

Hello, World!	| Goodbye, World!
Second Line	  Second Line
Gentoo Linux	  Gentoo Linux
Another Line	| Different Line

diff3

diff3 compares three different files line-by-line. This will use the file output from the sdiff section in its examples.

Comparing three different files

Comparing files with this is similar to using diff:

user $diff3 one two output

====2
1:1c
3:1c
  Hello, World!
2:1c
  Goodbye, World!
====1
1:4c
  Another Line
2:4c
3:4c
  Different Line

sdiff

sdiff is similar to using diff's -y argument to display columns

Displaying the difference

user $sdiff one two

Hello, World!	| Goodbye, World!
Second Line	  Second Line
Gentoo Linux	  Gentoo Linux
Another Line	| Different Line

Merging the differences

To go line-by-line and pick the differences to include in an output file, use the -o argument:

user $sdiff one two -o output

Hello, World!	| Goodbye, World!
%?
ed:	Edit then use both versions, each decorated with a header.
eb:	Edit then use both versions.
el or e1:	Edit then use the left version.
er or e2:	Edit then use the right version.
e:	Discard both versions then edit a new one.
l or 1:	Use the left version.
r or 2:	Use the right version.
s:	Silently include common lines.
v:	Verbosely include common lines.
q:	Quit.
%l
Second Line	  Second Line
Gentoo Linux	  Gentoo Linux
Another Line	| Different Line
%r

This should now be in the output file:

FILE output

Hello, World!
Second Line
Gentoo Linux
Different Line