ter Smitten's

While applying some (550) changesets I needed some good tools to show me the differences between files and revisions.

The first one I found very useful was:

svn diff --diff-cmd diff -x -uw -r REV1:REV2 FILE;

which is even better in combination with colordiff:

apt-get install colordiff;
svn diff --diff-cmd diff -x -uw -r REV1:REV2 FILE | colordiff;

An other great tool is vimdiff, which starts Vim as usual, and additionally sets it up for viewing the differences between files. Here’s how I use it:

sudo apt-get install vim;
vimdiff -O -c 'set diffopt+=iwhite,filler' FILE1 FILE2;

Some of you will probably prefer Meld, which is a visual diff and merge tool.

To combine the powers of all three I created a simple (Bash) wrapper. It downloads two revisions (svn) of a file and compares them using a diff tool of choice:

#!/bin/bash
#
# set -x;
#
if [ -z "${1}" ] || [ -z "${2}" ] || [ -z "${3}" ]; then

  echo "";
  echo "Use the script as discribed below:";
  echo "$0 [ filename ] [ revision1 ] [ revision2 ] [ diff tool (optionally) ]";
  echo "";

else

  pid=$$;

  filename="${1}";
  revision1="${2}";
  revision2="${3}";
  diff_command="${4}";

  temp1="/tmp/${pid}.${revision1}.${filename}";
  temp2="/tmp/${pid}.${revision2}.${filename}";

  trap trap_function 0 1 2 15;

  trap_function()
  {
    if [ -f "${temp1}" ]; then

      rm "${temp1}";

    fi

    if [ -f "${temp2}" ]; then

      rm "${temp2}";

    fi
  }

  svn cat "${filename}" -r "${revision1}" > "${temp1}";
  svn cat "${filename}" -r "${revision2}" > "${temp2}";

  if [ "${diff_command}" == "vimdiff" ]; then

    vimdiff -O -c 'set diffopt+=iwhite,filler' "${temp1}" "${temp2}";

  elif [ "${diff_command}" == "meld" ]; then

    meld --diff "${temp1}" "${temp2}";

  else

    diff -uw "${temp1}" "${temp2}" | colordiff;

  fi

fi