diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 38ae68d..035508a 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -14,56 +14,68 @@ jobs:
         image: registry:2
         ports:
           - 5000:5000
-    name: Test stacker-build action
+    name: Test stacker-build-push-action
     steps:
       - uses: actions/checkout@v2
 
       - name: Run stacker-build with all build inputs
         uses: ./
         with:
-          stackerfile: 'test/stacker.yaml'
-          substitutes: 'SUB1=VAR1 SUB2=VAR2 SUB3=VAR3'
+          file: 'test/stacker.yaml'
+          build-args: |
+            SUB1=VAR1
+            SUB2=VAR2
+            SUB3=VAR3
           layer-type: 'tar squashfs'
 
-      - name: Run stacker-build with only substitutes
+      - name: Run stacker-build with only build-args
         uses: ./
         with:
-          stackerfile: 'test/stacker.yaml'
-          substitutes: 'SUB1=VAR1 SUB2=VAR2 SUB3=VAR3'
+          file: 'test/stacker.yaml'
+          build-args: |
+            SUB1=VAR1
+            SUB2=VAR2
+            SUB3=VAR3
 
       - name: Run stacker-build with only layer-type
         uses: ./
         with:
-          stackerfile: 'test/stacker_wo_subs.yaml'
+          file: 'test/stacker_wo_subs.yaml'
           layer-type: 'tar squashfs'
 
-      - name: Run stacker-build with only stackerfile
+      - name: Run stacker-build with only file input
         uses: ./
         with:
-          stackerfile: 'test/stacker_wo_subs.yaml'
+          file: 'test/stacker_wo_subs.yaml'
       
       - name: Run stacker-build with push and tags
         uses: ./
         with:
-          stackerfile: 'test/stacker_wo_subs.yaml'
+          file: 'test/stacker_wo_subs.yaml'
           tags: v1 latest
           url: docker://localhost:5000/name/app
           skip-tls: true
       
-      - name: Run stacker-build with push, tags and substitutes
+      - name: Run stacker-build with push, tags and build-args
         uses: ./
         with:
-          stackerfile: 'test/stacker.yaml'
-          substitutes: 'SUB1=VAR1 SUB2=VAR2 SUB3=VAR3'
+          file: 'test/stacker.yaml'
+          build-args: |
+            SUB1=VAR1
+            SUB2=VAR2
+            SUB3=VAR3
           tags: v1 latest
           url: docker://localhost:5000/name/app
           skip-tls: true
       
-      - name: Run stacker-build with push, tags, substitutes and layer-type
+      - name: Run stacker-build with push, tags, build-args and layer-type
         uses: ./
         with:
-          stackerfile: 'test/stacker.yaml'
-          substitutes: 'SUB1=VAR1 SUB2=VAR2 SUB3=VAR3'
+          file: 'test/stacker.yaml'
+          build-args: |
+            SUB1=VAR1
+            SUB2=VAR2
+            SUB3=VAR3
           tags: v1 latest
           url: docker://localhost:5000/name/app
           layer-type: 'tar squashfs'
diff --git a/README.md b/README.md
index e6388e0..4a81597 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,9 @@
 # stacker-build-push-action
 # [![ci](https://github.com/project-stacker/stacker-build-push-action/actions/workflows/ci.yaml/badge.svg?branch=main)](https://github.com/project-stacker/stacker-build-push-action/actions)
 
-stacker build action builds OCI container images via a declarative yaml format.
+```stacker-build-push-action``` builds OCI container images via a declarative yaml format and publish them to OCI registries.
 
-stacker only works on Linux
+stacker only works on Linux!
 
 For more information about stacker tool see: https://github.com/project-stacker/stacker
 
@@ -12,16 +12,17 @@ For more information about stacker tool see: https://github.com/project-stacker/
 
 <a id="dockerfile-build-inputs"></a>
 
-| Input Name | Description | Default |
-| ---------- | ----------- | ------- |
-| stackerfile | the yaml file to be built as an OCI image, example: [stacker.yaml](./test/stacker.yaml)  | stacker.yaml
-| layer-type | output layer type (supported values: tar, squashfs), ca be both separated by whitespace | tar
-| substitutes | variable substitution in stackerfile, see [stacker.yaml doc](https://github.com/project-stacker/stacker/blob/master/doc/stacker_yaml.md) | None
-| url | remote OCI registry + repo name eg: docker://ghcr.io/project-stacker/ | None
-| tags | one or more tags to give the new image, separated by whitespace | None
-| username | used to login to registry | None
-| password | used to login to registry | None
-| skip-tls | used with unsecure (http) registries | false
+| Input Name | Type |  Description | Default |
+| ---------- | ---- |----------- | ------- |
+| file | string |the yaml file to be built as an OCI image, example: [stacker.yaml](./test/stacker.yaml)  | stacker.yaml
+| layer-type | list | output layer type (supported values: tar, squashfs), ca be both separated by whitespace | tar
+| build-args | list | the list of build-time arguments (subtitutes) separated by newline, see [stacker.yaml doc](https://github.com/project-stacker/stacker/blob/master/doc/stacker_yaml.md) | None
+| url | string | remote OCI registry + repo name eg: docker://ghcr.io/project-stacker/ | None
+| tags | list | one or more tags to give the new image, separated by whitespace | None
+| username | string | used to login to registry | None
+| password | string | used to login to registry | None
+| skip-tls | bool | used with unsecure (http) registries | false
+| token    | string |github token used to authenticate against a repository for Git context | ${{ github.token }}
 
 
 Build only example:
@@ -30,8 +31,11 @@ Build only example:
 - name: Run stacker-build
   uses: project-stacker/stacker-build-push-action@main
   with:
-    stackerfile: 'test/stacker.yaml'
-    substitutes: 'SUB1=VAR1 SUB2=VAR2 SUB3=VAR3'
+    file: 'test/stacker.yaml'
+    build-args: |
+      SUB1=VAR1
+      SUB2=VAR2
+      SUB3=VAR3
     layer-type: 'tar squashfs'
 ```
 
@@ -47,8 +51,11 @@ Build and push example to ghcr.io:
 - name: Run stacker-build
   uses: project-stacker/stacker-build-push-action@main
   with:
-    stackerfile: 'test/stacker.yaml'
-    substitutes: 'SUB1=VAR1 SUB2=VAR2 SUB3=VAR3'
+    file: 'test/stacker.yaml'
+    build-args: |
+      SUB1=VAR1
+      SUB2=VAR2
+      SUB3=VAR3
     layer-type: 'tar squashfs'
     tags: ${{ github.event.release.tag_name }} latest
     url: docker://ghcr.io/${{ github.repository }}
@@ -66,8 +73,11 @@ Build and push example to localhost:
 - name: Run stacker-build
   uses: project-stacker/stacker-build-push-action@main
   with:
-    stackerfile: 'test/stacker.yaml'
-    substitutes: 'SUB1=VAR1 SUB2=VAR2 SUB3=VAR3'
+    file: 'test/stacker.yaml'
+    build-args: |
+      SUB1=VAR1
+      SUB2=VAR2
+      SUB3=VAR3
     layer-type: 'tar squashfs'
     url: docker://localhost:5000
     skip-tls: true
diff --git a/action.yml b/action.yml
index d5f74f6..6958887 100644
--- a/action.yml
+++ b/action.yml
@@ -5,8 +5,8 @@ inputs:
     description: 'Which stacker version to use'
     required: false
     default: 'latest'
-  stackerfile:  # id of input
-    description: 'Which stackerfile to build'
+  file:
+    description: 'Which stacker file to build'
     required: true
     default: 'stacker.yaml'
   layer-type:
@@ -14,11 +14,11 @@ inputs:
     required: false
     default: "tar"
   token:
-    description: 'Used to pull stacker release binaries'
+    description: 'GitHub Token used to authenticate against a repository for Git context'
     required: false
     default: ${{ github.token }}
-  substitutes:
-    description: 'The list of subtitutes to make in stacker file separated by whitespace, eg: ONE=1 TWO=2 THREE=3'
+  build-args:
+    description: 'The list of build-time arguments separated by whitespace, eg: ONE=1 TWO=2 THREE=3'
     required: false
   tags:
     description: 'Tags used when pushing to remote OCI registry, separated by whitespace'
diff --git a/dist/index.js b/dist/index.js
index f9eba0d..bb55d18 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -23841,6 +23841,31 @@ function makeAvailableInPath(download, version) {
     });
 }
 
+;// CONCATENATED MODULE: ./src/utils.ts
+
+function splitByNewline(s) {
+    return s.split(/\r?\n/);
+}
+function getInputList(name) {
+    const items = core.getInput(name);
+    if (!items) {
+        return [];
+    }
+    const splitItems = splitByNewline(items);
+    return splitItems
+        .reduce((acc, line) => acc.concat(line).map((item) => item.trim()), []);
+}
+function getSpaceSeparatedInput(name) {
+    const items = core.getInput(name);
+    if (items.length === 0) {
+        core.debug("empty");
+        return [];
+    }
+    const splitItems = items.trim().split(/\s+/);
+    return splitItems
+        .reduce((acc, line) => acc.concat(line).map((item) => item.trim()), []);
+}
+
 ;// CONCATENATED MODULE: ./src/index.ts
 var src_awaiter = (undefined && undefined.__awaiter) || function (thisArg, _arguments, P, generator) {
     function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
@@ -23856,6 +23881,7 @@ var src_awaiter = (undefined && undefined.__awaiter) || function (thisArg, _argu
 
 
 
+
 const stackerBin = "stacker";
 const stackerOrg = "project-stacker";
 const stackerRepo = "stacker";
@@ -23879,29 +23905,17 @@ function run() {
         const stackerPath = yield io.which("stacker", true);
         const cli = new StackerCLI(stackerPath);
         yield cli.execute(["--version"], { group: true });
-        const stackerfile = core.getInput("stackerfile");
-        var substitutesList = [];
-        const substitutes = core.getInput("substitutes");
-        if (substitutes != "") {
-            substitutesList = substitutes.trim().split(/\s+/);
-        }
-        var layerTypeList = [];
-        const layerType = core.getInput("layer-type");
-        if (layerType != "") {
-            layerTypeList = layerType.trim().split(/\s+/);
-        }
-        yield cli.build(stackerfile, layerTypeList, substitutesList);
-        var tagsList = [];
-        const tags = core.getInput("tags");
-        if (tags != "") {
-            tagsList = tags.trim().split(/\s+/);
-        }
+        const stackerfile = core.getInput("file");
+        const substitutes = getInputList("build-args");
+        const layerTypes = getSpaceSeparatedInput("layer-type");
+        yield cli.build(stackerfile, layerTypes, substitutes);
+        const tags = getSpaceSeparatedInput("tags");
         const registryURL = core.getInput("url");
         const username = core.getInput("username");
         const password = core.getInput("password");
         const skipTLS = core.getInput("skip-tls") === "true";
         if (registryURL) {
-            yield cli.publish(stackerfile, layerTypeList, substitutesList, registryURL, tagsList, username, password, skipTLS);
+            yield cli.publish(stackerfile, layerTypes, substitutes, registryURL, tags, username, password, skipTLS);
         }
     });
 }
diff --git a/src/index.ts b/src/index.ts
index 6a427fa..3285ef9 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -4,6 +4,7 @@ import * as tc from "@actions/tool-cache";
 
 import { StackerCLI } from "./stacker";
 import * as installer from "./installer";
+import * as utils from "./utils";
 
 export const stackerBin = "stacker";
 export const stackerOrg = "project-stacker";
@@ -37,28 +38,18 @@ export async function run(): Promise<void> {
     await cli.execute(["--version"], { group: true });
 
     // get stacker file path from input
-    const stackerfile = core.getInput("stackerfile");
+    const stackerfile = core.getInput("file");
 
-    // get substitutes from input
-    var substitutesList: string[] = [];
-    const substitutes = core.getInput("substitutes");
-    if (substitutes != "") {
-        substitutesList = substitutes.trim().split(/\s+/);
-    }
+    // get build-args from input
+    const substitutes = utils.getInputList("build-args");
 
-    var layerTypeList: string[] = [];
-    const layerType = core.getInput("layer-type");
-    if (layerType != "") {
-        layerTypeList = layerType.trim().split(/\s+/);
-    }
+    // get layer-type from input
+    const layerTypes = utils.getSpaceSeparatedInput("layer-type");
 
-    await cli.build(stackerfile, layerTypeList, substitutesList);
+    await cli.build(stackerfile, layerTypes, substitutes);
 
-    var tagsList: string[] = [];
-    const tags = core.getInput("tags");
-    if (tags != "") {
-        tagsList = tags.trim().split(/\s+/);
-    }
+    // get tags from input
+    const tags = utils.getSpaceSeparatedInput("tags");
 
     const registryURL = core.getInput("url");
     const username = core.getInput("username");
@@ -66,8 +57,8 @@ export async function run(): Promise<void> {
     const skipTLS = core.getInput("skip-tls") === "true";
 
     if (registryURL) {
-        await cli.publish(stackerfile, layerTypeList, substitutesList,
-            registryURL, tagsList, username, password, skipTLS);
+        await cli.publish(stackerfile, layerTypes, substitutes,
+            registryURL, tags, username, password, skipTLS);
     }
 }
 
diff --git a/src/utils.ts b/src/utils.ts
new file mode 100644
index 0000000..4ba962b
--- /dev/null
+++ b/src/utils.ts
@@ -0,0 +1,33 @@
+import * as core from "@actions/core";
+
+export function splitByNewline(s: string): string[] {
+    return s.split(/\r?\n/);
+}
+
+export function getInputList(name: string): string[] {
+    const items = core.getInput(name);
+    if (!items) {
+        return [];
+    }
+    const splitItems = splitByNewline(items);
+    return splitItems
+        .reduce<string[]>(
+            (acc, line) => acc.concat(line).map((item) => item.trim()),
+            [],
+        );
+}
+
+export function getSpaceSeparatedInput(name: string): string[] {
+    const items = core.getInput(name);
+    if (items.length === 0) {
+        core.debug("empty");
+        return [];
+    }
+    const splitItems = items.trim().split(/\s+/);
+
+    return splitItems
+        .reduce<string[]>(
+            (acc, line) => acc.concat(line).map((item) => item.trim()),
+            [],
+        );
+}