diff --git a/src/main/java/com/google/devtools/build/lib/analysis/BashCommandConstructor.java b/src/main/java/com/google/devtools/build/lib/analysis/BashCommandConstructor.java
new file mode 100644
index 0000000..41b2488
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/analysis/BashCommandConstructor.java
@@ -0,0 +1,50 @@
+// Copyright 2019 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.analysis;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.actions.FileWriteAction;
+import com.google.devtools.build.lib.vfs.PathFragment;
+
+/** The class for constructing command line for Bash. */
+public final class BashCommandConstructor implements CommandConstructor {
+
+  private final PathFragment shellPath;
+  private final String scriptNameSuffix;
+
+  BashCommandConstructor(PathFragment shellPath, String scriptNameSuffix) {
+    this.shellPath = shellPath;
+    this.scriptNameSuffix = scriptNameSuffix;
+  }
+
+  @Override
+  public ImmutableList<String> asExecArgv(Artifact scriptFileArtifact) {
+    return ImmutableList.of(shellPath.getPathString(), scriptFileArtifact.getExecPathString());
+  }
+
+  @Override
+  public ImmutableList<String> asExecArgv(String command) {
+    return ImmutableList.of(shellPath.getPathString(), "-c", command);
+  }
+
+  @Override
+  public Artifact commandAsScript(RuleContext ruleContext, String command) {
+    String scriptFileName = ruleContext.getTarget().getName() + scriptNameSuffix;
+    String scriptFileContents = "#!/bin/bash\n" + command;
+    return FileWriteAction.createFile(
+        ruleContext, scriptFileName, scriptFileContents, /*executable=*/ true);
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/CommandConstructor.java b/src/main/java/com/google/devtools/build/lib/analysis/CommandConstructor.java
new file mode 100644
index 0000000..6fd2023
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/analysis/CommandConstructor.java
@@ -0,0 +1,37 @@
+// Copyright 2019 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.analysis;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.actions.Artifact;
+
+/**
+ * The interface to construct command line for different shells (Bash, Batch, Powershell). Used in
+ * {@link com.google.devtools.build.lib.analysis.CommandHelper}
+ */
+public interface CommandConstructor {
+
+  /**
+   * Given a string of command, return the arguments to run the command. eg. For Bash command,
+   * asExecArgv("foo bar") -> ["/bin/bash", "-c", "foo bar"]
+   */
+  ImmutableList<String> asExecArgv(String command);
+
+  /** Given an artifact of a script, return the arguments to run this command. */
+  ImmutableList<String> asExecArgv(Artifact scriptFileArtifact);
+
+  /** Write the command to a script and return the artifact of the script. */
+  Artifact commandAsScript(RuleContext ruleContext, String command);
+}
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java b/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
index 2cd8184..4572e11 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
@@ -23,7 +23,6 @@
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.ExecutionRequirements;
 import com.google.devtools.build.lib.actions.RunfilesSupplier;
-import com.google.devtools.build.lib.analysis.actions.FileWriteAction;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget.Mode;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
@@ -283,38 +282,19 @@
   }
 
   private static Pair<List<String>, Artifact> buildCommandLineMaybeWithScriptFile(
-      RuleContext ruleContext, String command, String scriptPostFix, PathFragment shellPath) {
+      RuleContext ruleContext, String command, CommandConstructor constructor) {
     List<String> argv;
     Artifact scriptFileArtifact = null;
     if (command.length() <= maxCommandLength) {
-      argv = buildCommandLineSimpleArgv(command, shellPath);
+      argv = constructor.asExecArgv(command);
     } else {
       // Use script file.
-      scriptFileArtifact = buildCommandLineArtifact(ruleContext, command, scriptPostFix);
-      argv = buildCommandLineArgvWithArtifact(scriptFileArtifact, shellPath);
+      scriptFileArtifact = constructor.commandAsScript(ruleContext, command);
+      argv = constructor.asExecArgv(scriptFileArtifact);
     }
     return Pair.of(argv, scriptFileArtifact);
   }
 
-  private static ImmutableList<String> buildCommandLineArgvWithArtifact(Artifact scriptFileArtifact,
-      PathFragment shellPath) {
-    return ImmutableList.of(shellPath.getPathString(), scriptFileArtifact.getExecPathString());
-  }
-
-  private static Artifact buildCommandLineArtifact(RuleContext ruleContext, String command,
-      String scriptPostFix) {
-    String scriptFileName = ruleContext.getTarget().getName() + scriptPostFix;
-    String scriptFileContents = "#!/bin/bash\n" + command;
-    Artifact scriptFileArtifact = FileWriteAction.createFile(
-        ruleContext, scriptFileName, scriptFileContents, /*executable=*/true);
-    return scriptFileArtifact;
-  }
-
-  private static ImmutableList<String> buildCommandLineSimpleArgv(String command,
-      PathFragment shellPath) {
-    return ImmutableList.of(shellPath.getPathString(), "-c", command);
-  }
-
   /**
    * If {@code command} is too long, creates a helper shell script that runs that command.
    *
@@ -324,49 +304,24 @@
    * this method does nothing and returns null.
    */
   @Nullable
-  public static Artifact shellCommandHelperScriptMaybe(
-      RuleContext ruleCtx,
-      String command,
-      String scriptPostFix,
-      Map<String, String> executionInfo) {
+  public static Artifact commandHelperScriptMaybe(
+      RuleContext ruleCtx, String command, CommandConstructor constructor) {
     if (command.length() <= maxCommandLength) {
       return null;
     } else {
-      return buildCommandLineArtifact(ruleCtx, command, scriptPostFix);
+      return constructor.commandAsScript(ruleCtx, command);
     }
   }
 
   /**
-   * Builds the set of command-line arguments. Creates a bash script if the command line is longer
-   * than the allowed maximum {@link #maxCommandLength}. Fixes up the input artifact list with the
-   * created bash script when required.
-   */
-  public List<String> buildCommandLine(
-      PathFragment shExecutable,
-      String command,
-      NestedSetBuilder<Artifact> inputs,
-      String scriptPostFix) {
-    return buildCommandLine(
-        shExecutable, command, inputs, scriptPostFix, ImmutableMap.<String, String>of());
-  }
-
-  /**
    * Builds the set of command-line arguments using the specified shell path. Creates a bash script
    * if the command line is longer than the allowed maximum {@link #maxCommandLength}. Fixes up the
    * input artifact list with the created bash script when required.
-   *
-   * @param executionInfo an execution info map of the action associated with the command line to be
-   *     built.
    */
   public List<String> buildCommandLine(
-      PathFragment shExecutable,
-      String command,
-      NestedSetBuilder<Artifact> inputs,
-      String scriptPostFix,
-      Map<String, String> executionInfo) {
+      String command, NestedSetBuilder<Artifact> inputs, CommandConstructor constructor) {
     Pair<List<String>, Artifact> argvAndScriptFile =
-        buildCommandLineMaybeWithScriptFile(
-            ruleContext, command, scriptPostFix, shellPath(executionInfo, shExecutable));
+        buildCommandLineMaybeWithScriptFile(ruleContext, command, constructor);
     if (argvAndScriptFile.second != null) {
       inputs.add(argvAndScriptFile.second);
     }
@@ -379,14 +334,9 @@
    * created bash script when required.
    */
   public List<String> buildCommandLine(
-      PathFragment shExecutable,
-      String command,
-      List<Artifact> inputs,
-      String scriptPostFix,
-      Map<String, String> executionInfo) {
+      String command, List<Artifact> inputs, CommandConstructor constructor) {
     Pair<List<String>, Artifact> argvAndScriptFile =
-        buildCommandLineMaybeWithScriptFile(
-            ruleContext, command, scriptPostFix, shellPath(executionInfo, shExecutable));
+        buildCommandLineMaybeWithScriptFile(ruleContext, command, constructor);
     if (argvAndScriptFile.second != null) {
       inputs.add(argvAndScriptFile.second);
     }
@@ -394,10 +344,16 @@
   }
 
   /** Returns the path to the shell for an action with the given execution requirements. */
-  private PathFragment shellPath(Map<String, String> executionInfo, PathFragment shExecutable) {
+  private static PathFragment shellPath(
+      Map<String, String> executionInfo, PathFragment shExecutable) {
     // Use vanilla /bin/bash for actions running on mac machines.
     return executionInfo.containsKey(ExecutionRequirements.REQUIRES_DARWIN)
         ? PathFragment.create("/bin/bash")
         : shExecutable;
   }
+
+  public static BashCommandConstructor buildBashCommandConstructor(
+      Map<String, String> executionInfo, PathFragment shExecutable, String scriptPostFix) {
+    return new BashCommandConstructor(shellPath(executionInfo, shExecutable), scriptPostFix);
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/extra/ExtraActionSpec.java b/src/main/java/com/google/devtools/build/lib/analysis/extra/ExtraActionSpec.java
index 5c17eff..56b1786 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/extra/ExtraActionSpec.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/extra/ExtraActionSpec.java
@@ -23,6 +23,7 @@
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.CommandLine;
 import com.google.devtools.build.lib.actions.RunfilesSupplier;
+import com.google.devtools.build.lib.analysis.BashCommandConstructor;
 import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
@@ -129,13 +130,10 @@
         actionToShadow.getPrimaryOutput().getExecPath().getBaseName()
             + "."
             + actionToShadow.getKey(owningRule.getActionKeyContext());
-    List<String> argv =
-        commandHelper.buildCommandLine(
-            shExecutable,
-            command,
-            extraActionInputs,
-            "." + actionUniquifier + ".extra_action_script.sh",
-            executionInfo);
+    BashCommandConstructor constructor =
+        CommandHelper.buildBashCommandConstructor(
+            executionInfo, shExecutable, "." + actionUniquifier + ".extra_action_script.sh");
+    List<String> argv = commandHelper.buildCommandLine(command, extraActionInputs, constructor);
 
     String commandMessage = String.format("Executing extra_action %s on %s", label, ownerLabel);
     owningRule.registerAction(
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkActionFactory.java b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkActionFactory.java
index 16dea75..9cfd02e 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkActionFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkActionFactory.java
@@ -34,6 +34,7 @@
 import com.google.devtools.build.lib.actions.SingleStringArgFormatter;
 import com.google.devtools.build.lib.actions.extra.ExtraActionInfo;
 import com.google.devtools.build.lib.actions.extra.SpawnInfo;
+import com.google.devtools.build.lib.analysis.BashCommandConstructor;
 import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
 import com.google.devtools.build.lib.analysis.PseudoAction;
@@ -324,10 +325,12 @@
           ImmutableMap.copyOf(TargetUtils.getExecutionInfo(ruleContext.getRule()));
       String helperScriptSuffix = String.format(".run_shell_%d.sh", runShellOutputCounter++);
       String command = (String) commandUnchecked;
-      Artifact helperScript =
-          CommandHelper.shellCommandHelperScriptMaybe(
-              ruleContext, command, helperScriptSuffix, executionInfo);
       PathFragment shExecutable = ShToolchain.getPathOrError(ruleContext);
+      BashCommandConstructor constructor =
+          CommandHelper.buildBashCommandConstructor(
+              executionInfo, shExecutable, helperScriptSuffix);
+      Artifact helperScript =
+          CommandHelper.commandHelperScriptMaybe(ruleContext, command, constructor);
       if (helperScript == null) {
         builder.setShellCommand(shExecutable, command);
       } else {
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleContext.java b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleContext.java
index d9c821e..51e1980 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleContext.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleContext.java
@@ -30,6 +30,7 @@
 import com.google.devtools.build.lib.actions.ArtifactRoot;
 import com.google.devtools.build.lib.analysis.ActionsProvider;
 import com.google.devtools.build.lib.analysis.AliasProvider;
+import com.google.devtools.build.lib.analysis.BashCommandConstructor;
 import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.ConfigurationMakeVariableContext;
 import com.google.devtools.build.lib.analysis.DefaultInfo;
@@ -1067,15 +1068,15 @@
                 String.class,
                 "execution_requirements"));
     PathFragment shExecutable = ShToolchain.getPathOrError(ruleContext);
-    List<String> argv =
-        helper.buildCommandLine(
+
+    BashCommandConstructor constructor =
+        CommandHelper.buildBashCommandConstructor(
+            executionRequirements,
             shExecutable,
-            command,
-            inputs,
             // Hash the command-line to prevent multiple actions from the same rule invocation
             // conflicting with each other.
-            "." + Hashing.murmur3_32().hashUnencodedChars(command).toString() + SCRIPT_SUFFIX,
-            executionRequirements);
+            "." + Hashing.murmur3_32().hashUnencodedChars(command).toString() + SCRIPT_SUFFIX);
+    List<String> argv = helper.buildCommandLine(command, inputs, constructor);
     return Tuple.<Object>of(
         MutableList.copyOf(env, inputs),
         MutableList.copyOf(env, argv),
diff --git a/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java b/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java
index 37f048c..1557657 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java
@@ -23,6 +23,7 @@
 import com.google.devtools.build.lib.actions.CompositeRunfilesSupplier;
 import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
 import com.google.devtools.build.lib.analysis.AliasProvider;
+import com.google.devtools.build.lib.analysis.CommandConstructor;
 import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.ConfigurationMakeVariableContext;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
@@ -167,13 +168,12 @@
     if (ruleContext.hasErrors()) {
       return null;
     }
-    List<String> argv =
-        commandHelper.buildCommandLine(
-            shExecutable,
-            command,
-            inputs,
-            ".genrule_script.sh",
-            ImmutableMap.copyOf(executionInfo));
+
+    CommandConstructor constructor =
+        CommandHelper.buildBashCommandConstructor(
+            executionInfo, shExecutable, ".genrule_script.sh");
+
+    List<String> argv = commandHelper.buildCommandLine(command, inputs, constructor);
 
     if (isStampingEnabled(ruleContext)) {
       inputs.add(ruleContext.getAnalysisEnvironment().getStableWorkspaceStatusArtifact());