how can I diff two sections of the same file?

Question

I have a source file with two similar yet subtly different sections. I\'d like to merge the two sections into one subroutine with a parameter that handles the subtle difference

Answer 1

i chose to rework @ordnungswidrig's answer into a bash function (i was only interested in the differences from a single file, but this could easily be changed to handle two different files...):

# find differences within a file giving start and end lines for both sections
function diff_sections {
  local fname=`basename $1`;
  local tempfile=`mktemp -t $fname`;
  head -$3 $1 | tail +$2 > $tempfile && head -$5 $1 | tail +$4 | diff -u $tempfile - ;
  rm $tempfile;
}

you call the function like so... diff_sections path/to/file 464 483 485 506

Answer 2

Any diff tool that lets you manually adjust the alignment will do the job. Diffuse (http://diffuse.sourceforge.net/) is my favourite and it also lets you manually adjust the alignment.

Answer 3

Emacs has ediff-regions-wordwise for this -- you can take two buffers (or just one) and select a region in each, which ediff will then show for comparison.

Answer 4

The linediff plugin for Vim works well for me. Visually select one section of your file and type :Linediff. Visually select the other section and type :Linediff. It will put vim in to vimdiff mode, showing only the two sections you highlighted previously. Type:LinediffReset to exit vimdiff mode.

More info:

https://unix.stackexchange.com/a/52759/32477

https://superuser.com/a/414958/199800

Answer 5

I use Beyond Compare.
It allows you to select a line on each side and say 'Align Manually'. This should work just fine for you.

Answer 6

KDiff3 is open source and available on several platforms including Win32 and Linux.

It has the "manual alignment" feature discussed by Gishu about Beyond Compare (which by the way I haven't been using personally but is considered a great tool by many people I know).

See this answer for more examples.