diff --git a/initbuilder/src/main/java/org/jclouds/initbuilder/InitBuilder.java b/initbuilder/src/main/java/org/jclouds/initbuilder/InitBuilder.java
index 981ae162b9..89d7e88d32 100644
--- a/initbuilder/src/main/java/org/jclouds/initbuilder/InitBuilder.java
+++ b/initbuilder/src/main/java/org/jclouds/initbuilder/InitBuilder.java
@@ -25,6 +25,7 @@ package org.jclouds.initbuilder;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
+import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 
@@ -33,6 +34,9 @@ import org.jclouds.initbuilder.domain.ShellToken;
 import org.jclouds.initbuilder.util.Utils;
 
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Function;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 
 /**
@@ -48,6 +52,9 @@ public class InitBuilder {
    @VisibleForTesting
    Map<String, String> variables = Maps.newHashMap();
 
+   @VisibleForTesting
+   List<String> variablesToUnset = Lists.newArrayList("path", "javaHome", "libraryPath");
+
    /**
     * Adds a switch statement to the script. If its value is found, it will invoke the corresponding
     * action.
@@ -73,6 +80,14 @@ public class InitBuilder {
       return this;
    }
 
+   /**
+    * Unsets a variable to ensure it is set within the script.
+    */
+   public InitBuilder unsetEnvironmentVariable(String name) {
+      variablesToUnset.add(checkNotNull(name, "name"));
+      return this;
+   }
+
    /**
     * Exports a variable inside the script
     */
@@ -92,15 +107,26 @@ public class InitBuilder {
     * @param osFamily
     *           whether to write a cmd or bash script.
     */
-   public String build(OsFamily osFamily) {
+   public String build(final OsFamily osFamily) {
       StringBuilder builder = new StringBuilder();
       builder.append(ShellToken.SHEBANG.to(osFamily));
-      builder.append(ShellToken.ZERO_PATH.to(osFamily));
+      builder.append(Utils.writeUnsetVariables(Lists.newArrayList(Iterables.transform(
+               variablesToUnset, new Function<String, String>() {
+
+                  @Override
+                  public String apply(String from) {
+                     if (ShellToken.tokenValueMap(osFamily).containsKey(from + "Variable"))
+                        return Utils.FUNCTION_UPPER_UNDERSCORE_TO_LOWER_CAMEL.apply(ShellToken
+                                 .tokenValueMap(osFamily).get(from + "Variable"));
+                     return from;
+                  }
+
+               })), osFamily));
+      builder.append(Utils.writeZeroPath(osFamily));
       builder.append(Utils.writeVariableExporters(variables, osFamily));
       for (Entry<String, Map<String, String>> entry : switchExec.entrySet()) {
          builder.append(Utils.writeSwitch(entry.getKey(), entry.getValue(), osFamily));
       }
       return builder.toString();
    }
-
 }
\ No newline at end of file
diff --git a/initbuilder/src/main/java/org/jclouds/initbuilder/domain/ShellToken.java b/initbuilder/src/main/java/org/jclouds/initbuilder/domain/ShellToken.java
index dacacc6577..6006ea9a3c 100644
--- a/initbuilder/src/main/java/org/jclouds/initbuilder/domain/ShellToken.java
+++ b/initbuilder/src/main/java/org/jclouds/initbuilder/domain/ShellToken.java
@@ -33,13 +33,13 @@ import com.google.common.collect.MapMaker;
 import com.google.common.collect.Maps;
 
 /**
- * Constants used in operating suy
+ * Constants used in shell scripting.
  * 
  * @author Adrian Cole
  */
 public enum ShellToken {
 
-   FS, PS, LF, SH, SOURCE, REM, ARGS, VARSTART, VAREND, SHEBANG, ZERO_PATH, EXE;
+   FS, PS, LF, SH, SOURCE, REM, ARGS, VARSTART, VAREND, SHEBANG, LIBRARY_PATH_VARIABLE;
 
    private static final Map<OsFamily, Map<String, String>> familyToTokenValueMap = new MapMaker()
             .makeComputingMap(new Function<OsFamily, Map<String, String>>() {
@@ -91,6 +91,13 @@ public enum ShellToken {
                case UNIX:
                   return "bash";
             }
+         case LIBRARY_PATH_VARIABLE:
+            switch (family) {
+               case WINDOWS:
+                  return "PATH";
+               case UNIX:
+                  return "LD_LIBRARY_PATH";
+            }
          case SOURCE:
             switch (family) {
                case WINDOWS:
@@ -133,20 +140,7 @@ public enum ShellToken {
                case UNIX:
                   return "#!/bin/bash\n";
             }
-         case ZERO_PATH:
-            switch (family) {
-               case WINDOWS:
-                  return "set PATH=c:\\windows\\;C:\\windows\\system32\r\n";
-               case UNIX:
-                  return "export PATH=/usr/ucb/bin:/bin:/usr/bin:/usr/sbin\n";
-            }
-         case EXE:
-            switch (family) {
-               case WINDOWS:
-                  return ".exe";
-               case UNIX:
-                  return "";
-            }
+
          default:
             throw new UnsupportedOperationException("token " + this + " not configured");
       }
diff --git a/initbuilder/src/main/java/org/jclouds/initbuilder/util/Utils.java b/initbuilder/src/main/java/org/jclouds/initbuilder/util/Utils.java
index 665a1c9e56..0c9066a044 100644
--- a/initbuilder/src/main/java/org/jclouds/initbuilder/util/Utils.java
+++ b/initbuilder/src/main/java/org/jclouds/initbuilder/util/Utils.java
@@ -23,6 +23,7 @@
  */
 package org.jclouds.initbuilder.util;
 
+import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.regex.Matcher;
@@ -31,7 +32,10 @@ import java.util.regex.Pattern;
 import org.jclouds.initbuilder.domain.OsFamily;
 
 import com.google.common.base.CaseFormat;
+import com.google.common.base.Function;
+import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Iterables;
 
 /**
  * Utilities used to build init scripts.
@@ -40,7 +44,25 @@ import com.google.common.collect.ImmutableMap;
  */
 public class Utils {
 
-   public static final Pattern pattern = Pattern.compile("\\{(.+?)\\}");
+   public static final LowerCamelToUpperUnderscore FUNCTION_LOWER_CAMEL_TO_UPPER_UNDERSCORE = new LowerCamelToUpperUnderscore();
+
+   public static final class LowerCamelToUpperUnderscore implements Function<String, String> {
+      @Override
+      public String apply(String from) {
+         return CaseFormat.LOWER_CAMEL.to(CaseFormat.UPPER_UNDERSCORE, from);
+      }
+   }
+
+   public static final UpperUnderscoreToLowerCamel FUNCTION_UPPER_UNDERSCORE_TO_LOWER_CAMEL = new UpperUnderscoreToLowerCamel();
+
+   public static final class UpperUnderscoreToLowerCamel implements Function<String, String> {
+      @Override
+      public String apply(String from) {
+         return CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_CAMEL, from);
+      }
+   }
+
+   private static final Pattern pattern = Pattern.compile("\\{(.+?)\\}");
 
    /**
     * replaces tokens that are expressed as <code>{token}</code>
@@ -98,6 +120,70 @@ public class Utils {
       return initializers.toString();
    }
 
+   public static final Map<OsFamily, String> OS_TO_POSITIONAL_VAR_PATTERN = ImmutableMap.of(
+            OsFamily.UNIX, "set {key}=$1\nshift\n", OsFamily.WINDOWS, "set {key}=%1\r\nshift\r\n");
+
+   public static final Map<OsFamily, String> OS_TO_LOCAL_VAR_PATTERN = ImmutableMap.of(
+            OsFamily.UNIX, "set {key}=\"{value}\"\n", OsFamily.WINDOWS, "set {key}={value}\r\n");
+
+   /**
+    * Writes an initialization statement for use inside a script or a function.
+    * 
+    * @param positionalVariablesInLowerCamelCase
+    *           - transfer the value of args into these statements. Note that there is no check to
+    *           ensure that all source args are indeed present.
+    */
+   public static String writePositionalVars(List<String> positionalVariablesInLowerCamelCase,
+            OsFamily family) {
+      StringBuilder initializers = new StringBuilder();
+      for (String variableInLowerCamelCase : positionalVariablesInLowerCamelCase) {
+         String key = CaseFormat.LOWER_CAMEL.to(CaseFormat.UPPER_UNDERSCORE,
+                  variableInLowerCamelCase);
+         initializers.append(replaceTokens(OS_TO_POSITIONAL_VAR_PATTERN.get(family), ImmutableMap
+                  .of("key", key)));
+      }
+      return initializers.toString();
+   }
+
+   /**
+    * Ensures that variables come from a known source instead of bleeding in from a profile
+    * 
+    * @param variablesInLowerCamelCase
+    *           - System variables to unset
+    */
+   public static String writeUnsetVariables(List<String> variablesInLowerCamelCase, OsFamily family) {
+      switch (family) {
+         case UNIX:
+            return String.format("unset %s\n", Joiner.on(' ').join(
+                     Iterables.transform(variablesInLowerCamelCase,
+                              FUNCTION_LOWER_CAMEL_TO_UPPER_UNDERSCORE)));
+         case WINDOWS:
+            StringBuilder initializers = new StringBuilder();
+            for (String variableInLowerCamelCase : variablesInLowerCamelCase) {
+               String key = CaseFormat.LOWER_CAMEL.to(CaseFormat.UPPER_UNDERSCORE,
+                        variableInLowerCamelCase);
+               initializers.append(replaceTokens(OS_TO_LOCAL_VAR_PATTERN.get(family), ImmutableMap
+                        .of("key", key, "value", "")));
+            }
+            return initializers.toString();
+         default:
+            throw new UnsupportedOperationException("unsupported os: " + family);
+      }
+
+   }
+
+   public static final Map<OsFamily, String> OS_TO_ZERO_PATH = ImmutableMap.of(OsFamily.WINDOWS,
+            "set PATH=c:\\windows\\;C:\\windows\\system32\r\n", OsFamily.UNIX,
+            "export PATH=/usr/ucb/bin:/bin:/usr/bin:/usr/sbin\n");
+
+   /**
+    * @return line used to zero out the path of the script such that basic commands such as unix ps
+    *         will work.
+    */
+   public static String writeZeroPath(OsFamily family) {
+      return OS_TO_ZERO_PATH.get(family);
+   }
+
    public static final Map<OsFamily, String> OS_TO_SWITCH_PATTERN = ImmutableMap.of(OsFamily.UNIX,
             "case ${variable} in\n", OsFamily.WINDOWS, "goto CASE%{variable}\r\n");
 
@@ -108,6 +194,25 @@ public class Utils {
             "{value})\n   {action}\n   ;;\n", OsFamily.WINDOWS,
             ":CASE_{value}\r\n   {action}\r\n   GOTO END_SWITCH\r\n");
 
+   /**
+    * Generates a switch statement based on {@code variable}. If its value is found to be a key in
+    * {@code valueToActions}, the corresponding action is invoked.
+    * 
+    * <p/>
+    * Ex. variable is {@code 1} - the first argument to the script<br/>
+    * and valueToActions is {"start" -> "echo hello", "stop" -> "echo goodbye"}<br/>
+    * the script created will respond accordingly:<br/>
+    * {@code ./script start }<br/>
+    * << returns hello<br/>
+    * {@code ./script stop }<br/>
+    * << returns goodbye<br/>
+    * 
+    * @param variable
+    *           - shell variable to switch on
+    * @param valueToActions
+    *           - case statements, if the value of the variable matches a key, the corresponding
+    *           value will be invoked.
+    */
    public static String writeSwitch(String variable, Map<String, String> valueToActions,
             OsFamily family) {
       StringBuilder switchClause = new StringBuilder();
diff --git a/initbuilder/src/test/java/org/jclouds/initbuilder/domain/ShellTokenTest.java b/initbuilder/src/test/java/org/jclouds/initbuilder/domain/ShellTokenTest.java
index ada6a93947..b7a1237830 100644
--- a/initbuilder/src/test/java/org/jclouds/initbuilder/domain/ShellTokenTest.java
+++ b/initbuilder/src/test/java/org/jclouds/initbuilder/domain/ShellTokenTest.java
@@ -40,9 +40,8 @@ public class ShellTokenTest {
    public void testTokenValueMapUNIX() {
       Map<String, String> expected = new ImmutableMap.Builder<String, String>().put("fs", "/").put(
                "ps", ":").put("lf", "\n").put("sh", "bash").put("source", ".").put("rem", "#").put(
-               "args", "$@").put("varstart", "$").put("varend", "").put("shebang", "#!/bin/bash\n")
-               .put("zeroPath", "export PATH=/usr/ucb/bin:/bin:/usr/bin:/usr/sbin\n")
-               .put("exe", "").build();
+               "args", "$@").put("varstart", "$").put("varend", "").put("libraryPathVariable",
+               "LD_LIBRARY_PATH").put("shebang", "#!/bin/bash\n").build();
 
       assertEquals(ShellToken.tokenValueMap(OsFamily.UNIX), expected);
    }
@@ -51,9 +50,7 @@ public class ShellTokenTest {
       Map<String, String> expected = new ImmutableMap.Builder<String, String>().put("fs", "\\")
                .put("ps", ";").put("lf", "\r\n").put("sh", "cmd").put("source", "@call").put("rem",
                         "@rem").put("args", "%*").put("varstart", "%").put("varend", "%").put(
-                        "shebang", "@echo off\r\n").put("zeroPath",
-                        "set PATH=c:\\windows\\;C:\\windows\\system32\r\n").put("exe", ".exe")
-               .build();
+                        "libraryPathVariable", "PATH").put("shebang", "@echo off\r\n").build();
 
       assertEquals(ShellToken.tokenValueMap(OsFamily.WINDOWS), expected);
    }
diff --git a/initbuilder/src/test/java/org/jclouds/initbuilder/util/UtilsTest.java b/initbuilder/src/test/java/org/jclouds/initbuilder/util/UtilsTest.java
index 11a1b0d6d9..f8c3902cb2 100644
--- a/initbuilder/src/test/java/org/jclouds/initbuilder/util/UtilsTest.java
+++ b/initbuilder/src/test/java/org/jclouds/initbuilder/util/UtilsTest.java
@@ -24,10 +24,13 @@
 package org.jclouds.initbuilder.util;
 
 import static org.testng.Assert.assertEquals;
+
 import java.io.UnsupportedEncodingException;
 
 import org.jclouds.initbuilder.domain.OsFamily;
 import org.testng.annotations.Test;
+
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 
 /**
@@ -53,6 +56,26 @@ public class UtilsTest {
                "set MAVEN_OPTS=-Xms128m -Xmx256m -XX:+HeapDumpOnOutOfMemoryError\r\n");
    }
 
+   public void testWritePositionalVarsUNIX() {
+      assertEquals(Utils.writePositionalVars(ImmutableList.of("host", "port"), OsFamily.UNIX),
+               "set HOST=$1\nshift\nset PORT=$1\nshift\n");
+   }
+
+   public void testWritePositionalVarsWindows() {
+      assertEquals(Utils.writePositionalVars(ImmutableList.of("host", "port"), OsFamily.WINDOWS),
+               "set HOST=%1\r\nshift\r\nset PORT=%1\r\nshift\r\n");
+   }
+
+   public void testWriteUnsetVariablesUNIX() {
+      assertEquals(Utils.writeUnsetVariables(ImmutableList.of("host", "port"), OsFamily.UNIX),
+               "unset HOST PORT\n");
+   }
+
+   public void testWriteUnsetVariablesWindows() {
+      assertEquals(Utils.writeUnsetVariables(ImmutableList.of("host", "port"), OsFamily.WINDOWS),
+               "set HOST=\r\nset PORT=\r\n");
+   }
+
    public void testWriteSwitchUNIX() {
       assertEquals(Utils.writeSwitch("i", ImmutableMap.of("0", "echo hello zero", "1",
                "echo hello one"), OsFamily.UNIX),
diff --git a/initbuilder/src/test/resources/test_script.bash b/initbuilder/src/test/resources/test_script.bash
index 77db713c9f..e7917baf4c 100644
--- a/initbuilder/src/test/resources/test_script.bash
+++ b/initbuilder/src/test/resources/test_script.bash
@@ -1,4 +1,5 @@
 #!/bin/bash
+unset PATH JAVA_HOME LD_LIBRARY_PATH
 export PATH=/usr/ucb/bin:/bin:/usr/bin:/usr/sbin
 export JAVA_HOME="/apps/jdk1.6"
 case $1 in
diff --git a/initbuilder/src/test/resources/test_script.cmd b/initbuilder/src/test/resources/test_script.cmd
index eb43eff7d6..95a7598e77 100644
--- a/initbuilder/src/test/resources/test_script.cmd
+++ b/initbuilder/src/test/resources/test_script.cmd
@@ -1,4 +1,7 @@
 @echo off
+set PATH=
+set JAVA_HOME=
+set PATH=
 set PATH=c:\windows\;C:\windows\system32
 set JAVA_HOME=/apps/jdk1.6
 goto CASE%1