[bash] unix diff side-to-side results?

How can I plot the results of a unix diff command side-to-side instead of one difference after the other? See below for an example:

    diff /tmp/test1  /tmp/test2
1,4c1,2
< asfdsadf
< asdfsad
< fsaf
< fdsadf
---
> asdfsafdsf
> saf
6,8d3
< sadf
< asdf
< sadf
10d4
< fasd
12,13c6,14
< sadfa
< fd
---
> sadf
> sadf
> sadf
> sadf
> sadf
> sadf
> sadf
> sadf
> safa

I would like to have something like:

diff /tmp/test1  /tmp/test2
1,4c1,2
< asfdsadf       > asdfsafdsf
< asdfsad        > saf       
< fsaf
< fdsadf
---
6,8d3
< sadf
< asdf
< sadf
10d4
< fasd
12,13c6,14
< sadfa               > sadf
< fd              > sadf
---               > sadf
              > sadf
              > sadf
              > sadf
              > sadf
              > sadf
              > safa

Use the -y option:

diff -y file1 file2

From icdiff's homepage:

Your terminal can display color, but most diff tools don't make good use of it. By highlighting changes, icdiff can show you the differences between similar files without getting in the way. This is especially helpful for identifying and understanding small changes within existing lines.

Instead of trying to be a diff replacement for all circumstances, the goal of icdiff is to be a tool you can reach for to get a better picture of what changed when it's not immediately obvious from diff.

IMHO, its output is much more readable than diff -y.

Try cdiff - View colored, incremental diff in workspace or from stdin with side by side and auto pager support.

You should have sdiff for side-by-side merge of file differences. Take a read of man sdiff for the full story.

You can use vimdiff.

Example:

vimdiff file1 file2

You can simply use:

diff -y fileA.txt fileB.txt | colordiff

It shows the output splitted in two colums and colorized! (colordiff)

You can use:

sdiff  file1 file2

or

diff -y file1 file2

or

vimdiff file1 file2

for side by side display.

diff -y --suppress-common-lines file1 file2

Enhanced diff command with color, side by side and alias

Let's say the file contents are like:

cat /tmp/test1.txt
1
2
3
4
5
8
9

and

cat /tmp/test2.txt
1
1.5
2
4
5
6
7

Now comparing side-by-side

diff --width=$COLUMNS --suppress-common-lines --side-by-side --color=always /tmp/test1.txt /tmp/test2.txt
                                                                              > 1.5
3                                                                             <
8                                                                             | 6
9                                                                             | 7

You can define alias to use

alias diff='diff --width=$COLUMNS --suppress-common-lines --side-by-side --color=always'

Then new diff result:

diff /tmp/test1.txt /tmp/test2.txt
                                                                              > 1.5
3                                                                             <
8                                                                             | 6
9                                                                             | 7

If your files have inconsistent use of spaces and tabs, you may find it helpful to include the -t argument to expand the tabs:

diff -ty file1 file2