diff --git a/.travis.yml b/.travis.yml
index 847a5f8..fc5f953 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -26,16 +26,16 @@
   - docker
 
 install:
-  - cp -r ./build/docker/scripts/*.sh ./build/docker/$DISTRO/scripts/
-  - travis_retry travis_wait docker build -q -t thrift-build build/docker/$DISTRO
+  - (travis_wait ./build/docker/check_unmodified.sh $DISTRO && touch .unmodified) || true
+  - if [ ! -f .unmodified ]; then travis_retry travis_wait docker build -q -t thrift-build:$DISTRO build/docker/$DISTRO; fi
 
 script:
-  - docker run --net=host -e BUILD_LIBS="$BUILD_LIBS" $BUILD_ENV -v $(pwd):/thrift/src -it thrift-build $BUILD_CMD $BUILD_ARG
+  - docker run --net=host -e BUILD_LIBS="$BUILD_LIBS" $BUILD_ENV -v $(pwd):/thrift/src -it thrift-build:$DISTRO build/docker/scripts/$SCRIPT $BUILD_ARG
 
 env:
   global:
     - TEST_NAME=""
-    - BUILD_CMD="none"
+    - SCRIPT="cmake.sh"
     - BUILD_ARG=""
     - BUILD_ENV="-e CC=clang -e CXX=clang++"
     - DISTRO=ubuntu
@@ -44,12 +44,12 @@
   matrix:
     # TODO: Break up by protocol types to avoid 50min limit
     - TEST_NAME="Cross Language Tests"
-      BUILD_CMD="../cross-test.sh"
+      SCRIPT="cross-test.sh"
       BUILD_ARG="--enable-tutorial=no"
       BUILD_ENV="-e CC=clang -e CXX=clang++ -e THRIFT_CROSSTEST_CONCURRENCY=4"
 
     - TEST_NAME="Cross Language Tests (Debian)"
-      BUILD_CMD="../cross-test.sh"
+      SCRIPT="cross-test.sh"
       BUILD_ARG="--enable-tutorial=no"
       BUILD_ENV="-e CC=clang -e CXX=clang++ -e THRIFT_CROSSTEST_CONCURRENCY=4"
       DISTRO=debian
@@ -57,78 +57,67 @@
     # TODO: Remove them once migrated to CMake
     # Autotools builds
     - TEST_NAME="C C++ C# D Erlang Haxe Go (automake)"
-      BUILD_CMD="../autotools.sh"
+      SCRIPT="autotools.sh"
       BUILD_ARG="--without-dart --without-haskell --without-java --without-lua --without-nodejs --without-perl --without-php --without-php_extension --without-python --without-ruby"
 
     - TEST_NAME="C C++ - GCC (automake)"
-      BUILD_CMD="../autotools.sh"
+      SCRIPT="autotools.sh"
       BUILD_ARG="--without-csharp --without-java --without-erlang --without-nodejs --without-lua --without-python --without-perl --without-php --without-php_extension --without-dart --without-ruby --without-haskell --without-go --without-haxe --without-d"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
 
     - TEST_NAME="Java Lua PHP Ruby Dart (automake)"
-      BUILD_CMD="../autotools.sh"
+      SCRIPT="autotools.sh"
       BUILD_ARG="--without-cpp --without-haskell --without-c_glib --without-csharp --without-d --without-erlang --without-go --without-haxe --without-nodejs --without-python --without-perl"
 
     # These are flaky (due to cabal and npm network/server failures) and also have lengthy output
     - TEST_NAME="Haskell Node.js Python Perl (automake)"
-      BUILD_CMD="../autotools.sh"
+      SCRIPT="autotools.sh"
       BUILD_ARG="--without-cpp --without-c_glib --without-csharp --without-d --without-dart --without-erlang --without-go --without-haxe --without-java --without-lua --without-php --without-php_extension --without-ruby"
 
     # CMake build
     - TEST_NAME="All"
-      BUILD_CMD="../cmake.sh"
 
     - TEST_NAME="All (Debian)"
-      BUILD_CMD="../cmake.sh"
       DISTRO=debian
 
     - TEST_NAME="C C++ - GCC"
-      BUILD_CMD="../cmake.sh"
       BUILD_LIBS="CPP C_GLIB TESTING TUTORIALS"
       BUILD_ARG="-DWITH_PYTHON=OFF -DWITH_JAVA=OFF -DWITH_HASKELL=OFF"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
 
     - TEST_NAME="C++ (Boost Thread)"
-      BUILD_CMD="../cmake.sh"
       BUILD_LIBS="CPP TESTING TUTORIALS"
       BUILD_ARG="-DWITH_BOOSTTHREADS=ON -DWITH_PYTHON=OFF -DWITH_C_GLIB=OFF -DWITH_JAVA=OFF -DWITH_HASKELL=OFF"
 
     - TEST_NAME="C++ (Boost Thread - GCC)"
-      BUILD_CMD="../cmake.sh"
       BUILD_LIBS="CPP TESTING TUTORIALS"
       BUILD_ARG="-DWITH_BOOSTTHREADS=ON -DWITH_PYTHON=OFF -DWITH_C_GLIB=OFF -DWITH_JAVA=OFF -DWITH_HASKELL=OFF"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
 
     - TEST_NAME="C++ (Std Thread)"
-      BUILD_CMD="../cmake.sh"
       BUILD_LIBS="CPP TESTING TUTORIALS"
       BUILD_ARG="-DWITH_STDTHREADS=ON -DCMAKE_CXX_FLAGS='-std=c++11' -DWITH_PYTHON=OFF -DWITH_C_GLIB=OFF -DWITH_JAVA=OFF -DWITH_HASKELL=OFF"
 
     - TEST_NAME="C++ (Std Thread - GCC)"
-      BUILD_CMD="../cmake.sh"
       BUILD_LIBS="CPP TESTING TUTORIALS"
       BUILD_ARG="-DWITH_STDTHREADS=ON -DCMAKE_CXX_FLAGS='-std=c++11' -DWITH_PYTHON=OFF -DWITH_C_GLIB=OFF -DWITH_JAVA=OFF -DWITH_HASKELL=OFF"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
 
     - TEST_NAME="Compiler (mingw)"
-      BUILD_CMD="../cmake.sh"
       BUILD_LIBS=""
       BUILD_ARG="-DCMAKE_TOOLCHAIN_FILE=../build/cmake/mingw32-toolchain.cmake -DBUILD_COMPILER=ON -DBUILD_LIBRARIES=OFF -DBUILD_TESTING=OFF -DBUILD_EXAMPLES=OFF"
       BUILD_ENV=""
 
     - TEST_NAME="All - GCC (CentOS)"
-      BUILD_CMD="../cmake.sh"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
       DISTRO=centos
 
     - TEST_NAME="C C++ - Clang (CentOS)"
-      BUILD_CMD="../cmake.sh"
       BUILD_LIBS="CPP C_GLIB TESTING TUTORIALS"
       BUILD_ARG="-DWITH_PYTHON=OFF -DWITH_JAVA=OFF -DWITH_HASKELL=OFF"
       DISTRO=centos
 
     - TEST_NAME="Python 2.6 (CentOS 6)"
-      BUILD_CMD="../cmake.sh"
       BUILD_LIBS="PYTHON TESTING TUTORIALS"
       BUILD_ARG="-DWITH_PYTHON=ON -DWITH_CPP=OFF -DWITH_JAVA=OFF -DWITH_HASKELL=OFF"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
@@ -136,20 +125,20 @@
 
     # Distribution
     - TEST_NAME="make dist"
-      BUILD_CMD="../make-dist.sh"
+      SCRIPT="make-dist.sh"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
 
     - TEST_NAME="Debian Packages"
-      BUILD_CMD="../dpkg.sh"
+      SCRIPT="dpkg.sh"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
 
     - TEST_NAME="make dist (Debian)"
-      BUILD_CMD="../make-dist.sh"
+      SCRIPT="make-dist.sh"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
       DISTRO=debian
 
     - TEST_NAME="Debian Packages (Debian)"
-      BUILD_CMD="../dpkg.sh"
+      SCRIPT="dpkg.sh"
       BUILD_ENV="-e CC=gcc -e CXX=g++"
       DISTRO=debian