diff --git a/clangify.sh b/clangify.sh
index bad86ca42..1f58e93b8 100755
--- a/clangify.sh
+++ b/clangify.sh
@@ -1,22 +1,184 @@
 #!/bin/bash
 
 # This script will run clang-format on all modified, non-3rd-party C++/Header files.
+# Never, ever, should this recieve a path with a newline in it. Don't bother proofing it for that.
 
-set -e
 
-if hash clang-format 2>/dev/null && hash git 2>/dev/null; then
-	files_to_clean=($(git diff --name-only $(git merge-base origin/master HEAD)))
+# use script dir and return on exit
+current=$PWD
+function cleanup {
+  cd $current
+}
+trap cleanup EXIT
+cd "${BASH_SOURCE%/*}/"
 
-	printf "%s\n" ${files_to_clean[@]} | \
-		xargs -I{} find '{}' \( -name "*.cpp" -o -name "*.h" \) \
-		-not -path "./cockatrice/src/qt-json/*" \
-		-not -path "./servatrice/src/smtp/*" \
-		-not -path "./common/sfmt/*" \
-		-not -path "./oracle/src/zip/*" \
-		-not -path "./build*/*" \
-		-exec clang-format -style=file -i {} \;
-	echo "Successfully formatted following files:"
-	printf "%s\n" ${files_to_clean[@]}
-else
-	echo "Please install clang-format and git to use this program"
+# defaults
+include=("common" \
+"cockatrice/src" \
+"oracle/src" \
+"servatrice/src")
+exclude=("cockatrice/src/qt-json" \
+"servatrice/src/smtp" \
+"common/sfmt" \
+"oracle/src/zip")
+exts=("cpp" "h")
+cf_cmd="clang-format"
+branch="origin/master"
+
+# parse options
+while [[ $@ ]]; do
+  case "$1" in
+    '-b'|'--branch')
+      branch=$2
+      set_branch=1
+      shift 2
+      ;;
+    '-c'|'--color-diff')
+      color=" --color=always"
+      mode=diff
+      shift
+      ;;
+    '-d'|'--diff')
+      mode=diff
+      shift
+      ;;
+    '-h'|'--help')
+      cat <<EOM
+A bash script to format your code using clang-format.
+If no options are given, all dirty files are edited in place.
+If <dir>s are given, all source files in those directories are checked, recursively.
+
+USAGE: $0 [option] [-b[ranch] <git branch or object>] [<dir> ...]
+
+DEFAULTS:
+Default includes are:
+  ${include[@]/%/
+ }
+Default excludes are:
+  ${exclude[@]/%/
+ }
+OPTIONS:
+    -b, --branch <branch>
+        Compare to this git branch and format only files that differ.
+        If unspecified it defaults to origin/master.
+        To not compare to a branch this has to be explicitly set to "".
+        When not comparing to a branch git will not be used at all and all valid files will be parsed.
+
+    -c, --color-diff
+        Display a colored diff. Implies --diff.
+        Only available on systems which support 'diff --color'.
+
+    -d, --diff
+        Display a diff. Implies --test.
+
+    -h, --help
+        Display this message and exit.
+
+    -n, --names
+        Display a list of filenames that require formatting. Implies --test.
+
+    -t, --test
+        Do not edit files in place. Set exit code to 1 if changes are required.
+
+EXIT CODES:
+    0 on a successful format or if no files require formatting.
+    1 if a file requires formatting.
+    2 if given incorrect arguments.
+    3 if clang-format could not be found.
+EOM
+      exit 0
+      ;;
+    '-n'|'--names')
+      mode=name
+      shift
+      ;;
+    '-t'|'--test')
+      mode=code
+      shift
+      ;;
+    '--')
+      shift
+      ;;
+    *)
+      include=() # empty includes
+      while [[ $@ ]]; do
+        if [[ -d $1 ]]; then
+          include+=("$1")
+          shift
+        else
+          echo "error in parsing arguments of $0: $1 is not a directory" >&2
+          exit 2 # input error
+        fi
+      done
+      if ! [[ $set_branch ]]; then
+        unset branch # unset branch if not set explicitly
+      fi
+      break
+      ;;
+  esac
+done
+
+# check availability of clang-format
+if ! hash $cf_cmd 2>/dev/null; then
+  echo "could not find $cf_cmd" >&2
+  # find any clang-format-x.x in /usr/bin
+  cf_cmd=$(find /usr/bin -regex '.*/clang-format-[0-9]+\.[0-9]+' -print -quit)
+  if [[ $cf_cmd ]]; then
+    echo "found $cf_cmd instead" >&2
+  else
+    exit 3 # special exit code for missing dependency
+  fi
 fi
+
+if [[ $branch ]]; then
+  # get all dirty files through git
+  if ! base=$(git merge-base ${branch} HEAD); then
+    echo "could not find git merge base" >&2
+    exit 2 # input error
+  fi
+  declare -a reg
+  for ex in ${exts[@]}; do
+    reg+=(${include[@]/%/.*\\.$ex\$})
+  done
+  names=$(git diff --name-only $base | grep ${reg[@]/#/-e ^})
+else
+  names=$(find ${include[@]} -type f -false ${exts[@]/#/-o -name *\\.})
+fi
+
+# filter excludes
+names=$(<<<"$names" grep -v ${exclude[@]/#/-e ^})
+
+if ! [[ $names ]]; then
+  exit 0 # nothing to format means format is successful!
+fi
+
+# format
+case $mode in
+  diff)
+    declare -i code=0
+    for name in ${names[@]}; do
+      if ! $cf_cmd "$name" | diff "$name" - -p $color; then
+        code=1
+      fi
+    done
+    exit $code
+    ;;
+  name)
+    declare -i code=0
+    for name in ${names[@]}; do
+      if ! $cf_cmd "$name" | diff "$name" - -q >/dev/null; then
+        echo "$name"
+        code=1
+      fi
+    done
+    exit $code
+    ;;
+  code)
+    for name in ${names[@]}; do
+      $cf_cmd "$name" | diff "$name" - -q >/dev/null || exit 1
+    done
+    ;;
+  *)
+    $cf_cmd -i $names
+    ;;
+esac