diff --git a/.eslintrc.js b/.eslintrc.js
index 8991103..f6d6b22 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -1199,10 +1199,10 @@ module.exports = {
           "error"
       ],
       "unicorn/no-null": [
-          "error"
+          "off"
       ],
       "unicorn/no-process-exit": [
-          "error"
+          "off"
       ],
       "unicorn/no-reduce": [
           "off"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 810c69c..a085b65 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## v0.7.1
+
+Show additional defaults in CLI help
+Fix missing address index in cli
+Added env var processing for GITHUB_TOKEN, GITHUB_REPOSITORY, GITHUB_REF and GTR_SEED
+As we now support env vars for the required options it is valid to have no command line parameters
+All parameter validation errors shown at once
+Added --no-color option
+
 ## v0.7.0
 
 Refactored to include CLI
diff --git a/README.md b/README.md
index 6703650..051f453 100644
--- a/README.md
+++ b/README.md
@@ -72,7 +72,7 @@ jobs:
     steps:
       - name: Tangle Release
         id: tangle_release
-        uses: iotaledger/gh-tangle-release@v0.7.0
+        uses: iotaledger/gh-tangle-release@v0.7.1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           IOTA_SEED: ${{ secrets.IOTA_SEED }}
@@ -107,7 +107,7 @@ gh-tangle-release
 You will then be presented with the following options.
 
 ```shell
-GitHub Tangle Release v0.7.0 🚀
+GitHub Tangle Release v0.7.1 🚀
 
 Usage: gh-tangle-release [options]
 
@@ -123,13 +123,22 @@ Options:
                               "https://nodes.iota.cafe:443")
   --depth <number>            Depth to use for attaching the transaction to the tangle (default: "3")
   --mwm <number>              Minimum weight magnitude to use for attaching the transaction to the tangle (default: "14")
-  --seed <string>             81 Tryte seed used to generate addresses
+  --seed <string>             81 Tryte seed used to generate addresses (required)
   --address-index <number>    Index number used to generate addresses (default: "0")
   --transaction-tag <string>  Tag to apply to the Tangle transaction (default: "GITHUB9RELEASE")
   --comment <string>          An optional comment to include in the Tangle transaction payload
   --explorer-url <string>     Url of the explorer to use for exploration link (default: "https://utils.iota.org/transaction/:hash")
+  --no-color                  Disable colored output
   --help                      Display help
 
+You can also supply some of the options through environment variables:
+   --github-token: GITHUB_TOKEN
+   --owner: GITHUB_REPOSITORY[0]
+   --repository: GITHUB_REPOSITORY[1]
+        where GITHUB_REPOSITORY is formatted owner/repository
+   --release-tag: GITHUB_REF
+   --seed: GTR_SEED
+
 
 Example: gh-tangle-release --github-token a4d936470cb3d66f5434f787c2500bde9764f --owner my-org --repository my-repo --release-tag v1.0.1 --seed AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
   ```
diff --git a/action/index.js b/action/index.js
index 67b98cb..4055911 100644
--- a/action/index.js
+++ b/action/index.js
@@ -2458,33 +2458,34 @@ const iota_1 = __webpack_require__(586);
  * @returns The config as non partial.
  */
 function sanitizeInput(config) {
+    const errors = [];
     if (!config.githubToken) {
-        throw new Error("You must provide the GitHub token option");
+        errors.push("You must provide the GitHub token option");
     }
     if (!config.owner) {
-        throw new Error("You must provide the owner option");
+        errors.push("You must provide the owner option");
     }
     if (!config.repository) {
-        throw new Error("You must provide the repository option");
+        errors.push("You must provide the repository option");
     }
     if (!config.releaseTag) {
-        throw new Error("You must provide the release tag option");
+        errors.push("You must provide the release tag option");
     }
     if (!config.seed) {
-        throw new Error("You must provide the seed option");
+        errors.push("You must provide the seed option");
     }
-    if (!/[9A-Z]/.test(config.seed)) {
-        throw new Error("The seed option must be 81 trytes [A-Z9]");
+    else if (!/[9A-Z]/.test(config.seed)) {
+        errors.push("The seed option must be 81 trytes [A-Z9]");
     }
-    if (config.seed.length !== 81) {
-        throw new Error(`The seed option must be 81 trytes [A-Z9], it is ${config.seed.length}`);
+    else if (config.seed.length !== 81) {
+        errors.push(`The seed option must be 81 trytes [A-Z9], it is ${config.seed.length}`);
     }
     config.transactionTag = config.transactionTag || "GITHUB9RELEASE";
     if (!/[9A-Z]/.test(config.transactionTag)) {
-        throw new Error("The transaction tag option must be 27 trytes [A-Z9] or less");
+        errors.push("The transaction tag option must be 27 trytes [A-Z9] or less");
     }
-    if (config.transactionTag.length >= 27) {
-        throw new Error(`The transaction tag option must be 27 trytes [A-Z9] or less, it is ${config.transactionTag.length}`);
+    if (config.transactionTag.length > 27) {
+        errors.push(`The transaction tag option must be 27 trytes [A-Z9] or less, it is ${config.transactionTag.length}`);
     }
     config.explorerUrl = config.explorerUrl || "https://utils.iota.org/transaction/:hash";
     config.node = config.node || "https://nodes.iota.cafe:443";
@@ -2518,15 +2519,18 @@ function sanitizeInput(config) {
     else {
         mwm = config.mwm;
     }
+    if (errors.length > 0) {
+        throw new Error(errors.join("\n"));
+    }
     return {
-        githubToken: config.githubToken,
-        owner: config.owner,
-        repository: config.repository,
-        releaseTag: config.releaseTag,
+        githubToken: config.githubToken || "",
+        owner: config.owner || "",
+        repository: config.repository || "",
+        releaseTag: config.releaseTag || "",
         node: config.node,
         depth,
         mwm,
-        seed: config.seed,
+        seed: config.seed || "",
         addressIndex,
         transactionTag: config.transactionTag,
         comment: config.comment,
diff --git a/dist/cli-core.js b/dist/cli-core.js
new file mode 100644
index 0000000..7507f59
--- /dev/null
+++ b/dist/cli-core.js
@@ -0,0 +1,138 @@
+"use strict";
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.cliCore = void 0;
+const chalk_1 = __importDefault(require("chalk"));
+const commander_1 = require("commander");
+const node_emoji_1 = __importDefault(require("node-emoji"));
+const core_1 = require("./core");
+/**
+ * Execute the cli core.
+ * @param argv The command line arguments.
+ * @param env The environment variables.
+ * @param display Method to output display.
+ */
+function cliCore(argv, env, display) {
+    return __awaiter(this, void 0, void 0, function* () {
+        const program = new commander_1.Command();
+        try {
+            const version = "0.7.1";
+            program
+                .storeOptionsAsProperties(false)
+                .passCommandToAction(false)
+                .name(chalk_1.default.yellowBright("gh-tangle-release"))
+                .version(version, "-v, --version", chalk_1.default.yellowBright("output the current version"))
+                .description(chalk_1.default.cyan("An application for creating a transaction on the IOTA Tangle from a GitHub release."))
+                .option("--github-token <string>", chalk_1.default.yellowBright("GitHub token for accessing your repository (required)"))
+                .option("--owner <string>", chalk_1.default.yellowBright("GitHub repository owner (required)"))
+                .option("--repository <string>", chalk_1.default.yellowBright("GitHub repository (required)"))
+                .option("--release-tag <string>", chalk_1.default.yellowBright("The release tag from the GitHub repository (required)"))
+                .option("--node <string>", chalk_1.default.yellowBright("Url of the node to use for attaching the transaction to the tangle"), "https://nodes.iota.cafe:443")
+                .option("--depth <number>", chalk_1.default.yellowBright("Depth to use for attaching the transaction to the tangle"), "3")
+                .option("--mwm <number>", chalk_1.default.yellowBright("Minimum weight magnitude to use for attaching the transaction to the tangle"), "14")
+                .option("--seed <string>", chalk_1.default.yellowBright("81 Tryte seed used to generate addresses (required)"))
+                .option("--address-index <number>", chalk_1.default.yellowBright("Index number used to generate addresses"), "0")
+                .option("--transaction-tag <string>", chalk_1.default.yellowBright("Tag to apply to the Tangle transaction"), "GITHUB9RELEASE")
+                .option("--comment <string>", chalk_1.default.yellowBright("An optional comment to include in the Tangle transaction payload"))
+                .option("--explorer-url <string>", chalk_1.default.yellowBright("Url of the explorer to use for exploration link"), "https://utils.iota.org/transaction/:hash")
+                .option("--no-color", chalk_1.default.yellowBright("Disable colored output"))
+                .helpOption("--help", chalk_1.default.yellowBright("Display help"));
+            program.parse(argv);
+            const opts = program.opts();
+            console.log(opts);
+            display(chalk_1.default.green(`GitHub Tangle Release v${version} ${opts.color === false ? "" : node_emoji_1.default.get("rocket")}\n`));
+            const envRepo = env.GITHUB_REPOSITORY ? env.GITHUB_REPOSITORY.split("/") : [];
+            if (envRepo.length === 2) {
+                opts.owner = opts.owner || envRepo[0];
+                opts.repository = opts.repository || envRepo[1];
+            }
+            const config = core_1.sanitizeInput({
+                githubToken: opts.githubToken || env.GITHUB_TOKEN,
+                owner: opts.owner,
+                repository: opts.repository,
+                releaseTag: opts.releaseTag || env.GITHUB_REF,
+                node: opts.node,
+                depth: opts.depth,
+                mwm: opts.mwm,
+                seed: opts.seed || env.GTR_SEED,
+                addressIndex: opts.addressIndex,
+                transactionTag: opts.transactionTag,
+                comment: opts.comment,
+                explorerUrl: opts.explorerUrl
+            });
+            display("Options:");
+            display(chalk_1.default.cyan("\tGitHub Token"), chalk_1.default.white("*******"));
+            display(chalk_1.default.cyan("\tOwner"), chalk_1.default.white(config.owner));
+            display(chalk_1.default.cyan("\tRepository"), chalk_1.default.white(config.repository));
+            display(chalk_1.default.cyan("\tRelease Tag"), chalk_1.default.white(config.releaseTag));
+            display(chalk_1.default.cyan("\tNode"), chalk_1.default.white(config.node));
+            display(chalk_1.default.cyan("\tDepth"), chalk_1.default.white(config.depth));
+            display(chalk_1.default.cyan("\tMWM"), chalk_1.default.white(config.mwm));
+            display(chalk_1.default.cyan("\tSeed"), chalk_1.default.white("*******"));
+            display(chalk_1.default.cyan("\tAddress Index"), chalk_1.default.white(config.addressIndex));
+            display(chalk_1.default.cyan("\tTransaction Tag"), chalk_1.default.white(config.transactionTag));
+            if (config.comment) {
+                display(chalk_1.default.cyan("\tComment"), chalk_1.default.white(config.comment));
+            }
+            display(chalk_1.default.cyan("\tExplorer Url"), chalk_1.default.white(config.explorerUrl));
+            display("");
+            try {
+                const transactionDetails = yield core_1.tangleRelease(config, message => display(chalk_1.default.green(message)));
+                display("Transaction Hash:", chalk_1.default.cyan(transactionDetails.hash));
+                display("You can view the transaction on the tangle at:", chalk_1.default.cyan(transactionDetails.url));
+                display(chalk_1.default.green("Complete"));
+            }
+            catch (err) {
+                display("");
+                display(createErrors(err));
+                process.exit(1);
+            }
+        }
+        catch (err) {
+            program.help(str => `${str}${createEnvHelp()}${createExample()}${createErrors(err)}`);
+            process.exit(1);
+        }
+    });
+}
+exports.cliCore = cliCore;
+/**
+ * Show an example on the console.
+ * @returns The example text.
+ */
+function createExample() {
+    // eslint-disable-next-line max-len
+    return chalk_1.default.magenta("\nExample: gh-tangle-release --github-token a4d936470cb3d66f5434f787c2500bde9764f --owner my-org --repository my-repo --release-tag v1.0.1 --seed AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n\n");
+}
+/**
+ * Show additional info about env vars.
+ * @returns The additional information.
+ */
+function createEnvHelp() {
+    return `
+${chalk_1.default.cyan("You can also supply some of the options through environment variables:")}
+   ${chalk_1.default.cyan("--github-token: GITHUB_TOKEN")}
+   ${chalk_1.default.cyan("--owner: GITHUB_REPOSITORY[0]")}
+   ${chalk_1.default.cyan("--repository: GITHUB_REPOSITORY[1]")}
+   ${chalk_1.default.cyan("     where GITHUB_REPOSITORY is formatted owner/repository")}
+   ${chalk_1.default.cyan("--release-tag: GITHUB_REF")}
+   ${chalk_1.default.cyan("--seed: GTR_SEED")}\n\n`;
+}
+/**
+ * Show the errors.
+ * @param error The error that was thrown.
+ * @returns The formatted errors.
+ */
+function createErrors(error) {
+    return chalk_1.default.red(`The following errors occurred:\n   ${error.message.replace(/\n/g, "\n   ")}`);
+}
diff --git a/dist/cli.js b/dist/cli.js
index 29e1311..472e37b 100644
--- a/dist/cli.js
+++ b/dist/cli.js
@@ -1,95 +1,11 @@
 #!/usr/bin/env node
 "use strict";
-var __importDefault = (this && this.__importDefault) || function (mod) {
-    return (mod && mod.__esModule) ? mod : { "default": mod };
-};
 Object.defineProperty(exports, "__esModule", { value: true });
-const chalk_1 = __importDefault(require("chalk"));
-const commander_1 = require("commander");
-const node_emoji_1 = __importDefault(require("node-emoji"));
-const core_1 = require("./core");
-const version = "0.7.0";
-console.log(chalk_1.default.green(`GitHub Tangle Release v${version} ${node_emoji_1.default.get("rocket")}\n`));
-const program = new commander_1.Command();
-program
-    .storeOptionsAsProperties(false)
-    .passCommandToAction(false);
-program
-    .name(chalk_1.default.yellowBright("gh-tangle-release"))
-    .version(version, "-v, --version", chalk_1.default.yellowBright("output the current version"))
-    .description(chalk_1.default.cyan("An application for creating a transaction on the IOTA Tangle from a GitHub release."))
-    .option("--github-token <string>", chalk_1.default.yellowBright("GitHub token for accessing your repository"))
-    .option("--owner <string>", chalk_1.default.yellowBright("GitHub repository owner"))
-    .option("--repository <string>", chalk_1.default.yellowBright("GitHub repository"))
-    .option("--release-tag <string>", chalk_1.default.yellowBright("The release tag from the GitHub repository"))
-    .option("--node <string>", chalk_1.default.yellowBright("Url of the node to use for attaching the transaction to the tangle"), "https://nodes.iota.cafe:443")
-    .option("--depth <number>", chalk_1.default.yellowBright("Depth to use for attaching the transaction to the tangle"), "3")
-    .option("--mwm <number>", chalk_1.default.yellowBright("Minimum weight magnitude to use for attaching the transaction to the tangle"), "14")
-    .option("--seed <string>", chalk_1.default.yellowBright("81 Tryte seed used to generate addresses"))
-    .option("--address-index <number>", chalk_1.default.yellowBright("Index number used to generate addresses", "0"))
-    .option("--transaction-tag <string>", chalk_1.default.yellowBright("Tag to apply to the Tangle transaction"))
-    .option("--comment <string>", chalk_1.default.yellowBright("An optional comment to include in the Tangle transaction payload"))
-    .option("--explorer-url <string>", chalk_1.default.yellowBright("Url of the explorer to use for exploration link"), "https://utils.iota.org/transaction/:hash")
-    .helpOption("--help", chalk_1.default.yellowBright("Display help"));
-if (process.argv.length === 2) {
-    program.help(str => `${str}${createExample()}`);
-}
-else {
-    try {
-        program.parse(process.argv);
-        const opts = program.opts();
-        const config = core_1.sanitizeInput({
-            githubToken: opts.githubToken,
-            owner: opts.owner,
-            repository: opts.repository,
-            releaseTag: opts.releaseTag,
-            node: opts.node,
-            depth: opts.depth,
-            mwm: opts.mwm,
-            seed: opts.seed,
-            // eslint-disable-next-line unicorn/no-null
-            addressIndex: null,
-            transactionTag: opts.transactionTag,
-            comment: opts.comment,
-            explorerUrl: opts.explorerUrl
-        });
-        console.log("Options:");
-        console.log(chalk_1.default.cyan("\tGitHub Token"), chalk_1.default.white("*******"));
-        console.log(chalk_1.default.cyan("\tOwner"), chalk_1.default.white(config.owner));
-        console.log(chalk_1.default.cyan("\tRepository"), chalk_1.default.white(config.repository));
-        console.log(chalk_1.default.cyan("\tRelease Tag"), chalk_1.default.white(config.releaseTag));
-        console.log(chalk_1.default.cyan("\tNode"), chalk_1.default.white(config.node));
-        console.log(chalk_1.default.cyan("\tDepth"), chalk_1.default.white(config.depth));
-        console.log(chalk_1.default.cyan("\tMWM"), chalk_1.default.white(config.mwm));
-        console.log(chalk_1.default.cyan("\tSeed"), chalk_1.default.white("*******"));
-        console.log(chalk_1.default.cyan("\tAddress Index"), chalk_1.default.white(config.addressIndex));
-        console.log(chalk_1.default.cyan("\tTransaction Tag"), chalk_1.default.white(config.transactionTag));
-        if (config.comment) {
-            console.log(chalk_1.default.cyan("\tComment"), chalk_1.default.white(config.comment));
-        }
-        console.log(chalk_1.default.cyan("\tExplorer Url"), chalk_1.default.white(config.explorerUrl));
-        console.log();
-        core_1.tangleRelease(config, message => console.log(chalk_1.default.green(message)))
-            .then(transactionDetails => {
-            console.log("Transaction Hash:", chalk_1.default.cyan(transactionDetails.hash));
-            console.log("You can view the transaction on the tangle at:", chalk_1.default.cyan(transactionDetails.url));
-            console.log(chalk_1.default.green("Complete"));
-        })
-            .catch(err => {
-            console.log();
-            console.error(chalk_1.default.red(err));
-            process.exit(1);
-        });
+const cli_core_1 = require("./cli-core");
+cli_core_1.cliCore(process.argv, process.env, (message, param) => {
+    process.stdout.write(message);
+    if (param) {
+        process.stdout.write(` ${param}`);
     }
-    catch (err) {
-        program.help(str => `${str}${chalk_1.default.red(`Error: ${err.message}`)}`);
-    }
-}
-/**
- * Show an example on the console.
- * @returns The example text.
- */
-function createExample() {
-    // eslint-disable-next-line max-len
-    return chalk_1.default.magenta("\nExample: gh-tangle-release --github-token a4d936470cb3d66f5434f787c2500bde9764f --owner my-org --repository my-repo --release-tag v1.0.1 --seed AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n");
-}
+    process.stdout.write("\n");
+}).catch(err => process.stderr.write(err.message));
diff --git a/dist/core.js b/dist/core.js
index 7248168..8420601 100644
--- a/dist/core.js
+++ b/dist/core.js
@@ -20,33 +20,34 @@ const iota_1 = require("./iota");
  * @returns The config as non partial.
  */
 function sanitizeInput(config) {
+    const errors = [];
     if (!config.githubToken) {
-        throw new Error("You must provide the GitHub token option");
+        errors.push("You must provide the GitHub token option");
     }
     if (!config.owner) {
-        throw new Error("You must provide the owner option");
+        errors.push("You must provide the owner option");
     }
     if (!config.repository) {
-        throw new Error("You must provide the repository option");
+        errors.push("You must provide the repository option");
     }
     if (!config.releaseTag) {
-        throw new Error("You must provide the release tag option");
+        errors.push("You must provide the release tag option");
     }
     if (!config.seed) {
-        throw new Error("You must provide the seed option");
+        errors.push("You must provide the seed option");
     }
-    if (!/[9A-Z]/.test(config.seed)) {
-        throw new Error("The seed option must be 81 trytes [A-Z9]");
+    else if (!/[9A-Z]/.test(config.seed)) {
+        errors.push("The seed option must be 81 trytes [A-Z9]");
     }
-    if (config.seed.length !== 81) {
-        throw new Error(`The seed option must be 81 trytes [A-Z9], it is ${config.seed.length}`);
+    else if (config.seed.length !== 81) {
+        errors.push(`The seed option must be 81 trytes [A-Z9], it is ${config.seed.length}`);
     }
     config.transactionTag = config.transactionTag || "GITHUB9RELEASE";
     if (!/[9A-Z]/.test(config.transactionTag)) {
-        throw new Error("The transaction tag option must be 27 trytes [A-Z9] or less");
+        errors.push("The transaction tag option must be 27 trytes [A-Z9] or less");
     }
-    if (config.transactionTag.length >= 27) {
-        throw new Error(`The transaction tag option must be 27 trytes [A-Z9] or less, it is ${config.transactionTag.length}`);
+    if (config.transactionTag.length > 27) {
+        errors.push(`The transaction tag option must be 27 trytes [A-Z9] or less, it is ${config.transactionTag.length}`);
     }
     config.explorerUrl = config.explorerUrl || "https://utils.iota.org/transaction/:hash";
     config.node = config.node || "https://nodes.iota.cafe:443";
@@ -80,15 +81,18 @@ function sanitizeInput(config) {
     else {
         mwm = config.mwm;
     }
+    if (errors.length > 0) {
+        throw new Error(errors.join("\n"));
+    }
     return {
-        githubToken: config.githubToken,
-        owner: config.owner,
-        repository: config.repository,
-        releaseTag: config.releaseTag,
+        githubToken: config.githubToken || "",
+        owner: config.owner || "",
+        repository: config.repository || "",
+        releaseTag: config.releaseTag || "",
         node: config.node,
         depth,
         mwm,
-        seed: config.seed,
+        seed: config.seed || "",
         addressIndex,
         transactionTag: config.transactionTag,
         comment: config.comment,
diff --git a/package-lock.json b/package-lock.json
index 6305765..56a293d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
     "name": "@iota/gh-tangle-release",
-    "version": "0.7.0",
+    "version": "0.7.1",
     "lockfileVersion": 1,
     "requires": true,
     "dependencies": {
diff --git a/package.json b/package.json
index 0a400e7..4388317 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@iota/gh-tangle-release",
-    "version": "0.7.0",
+    "version": "0.7.1",
     "description": "Create a release and adds metadata to the IOTA Tangle",
     "main": "dist/index.js",
     "module": "es/index.js",
diff --git a/src/cli-core.ts b/src/cli-core.ts
new file mode 100644
index 0000000..cc176b5
--- /dev/null
+++ b/src/cli-core.ts
@@ -0,0 +1,151 @@
+import chalk from "chalk";
+import { Command } from "commander";
+import emoji from "node-emoji";
+import { sanitizeInput, tangleRelease } from "./core";
+
+/**
+ * Execute the cli core.
+ * @param argv The command line arguments.
+ * @param env The environment variables.
+ * @param display Method to output display.
+ */
+export async function cliCore(
+    argv: string[],
+    env: { [id: string]: string | undefined },
+    display: (message: string, param?: string) => void): Promise<void> {
+    const program = new Command();
+
+    try {
+        const version = "0.7.1";
+
+        program
+            .storeOptionsAsProperties(false)
+            .passCommandToAction(false)
+            .name(chalk.yellowBright("gh-tangle-release"))
+            .version(version, "-v, --version", chalk.yellowBright("output the current version"))
+            .description(
+                chalk.cyan("An application for creating a transaction on the IOTA Tangle from a GitHub release."))
+            .option("--github-token <string>", chalk.yellowBright(
+                "GitHub token for accessing your repository (required)"))
+            .option("--owner <string>", chalk.yellowBright("GitHub repository owner (required)"))
+            .option("--repository <string>", chalk.yellowBright("GitHub repository (required)"))
+            .option("--release-tag <string>",
+                chalk.yellowBright("The release tag from the GitHub repository (required)"))
+            .option("--node <string>",
+                chalk.yellowBright("Url of the node to use for attaching the transaction to the tangle"),
+                "https://nodes.iota.cafe:443")
+            .option("--depth <number>", chalk.yellowBright("Depth to use for attaching the transaction to the tangle"),
+                "3")
+            .option("--mwm <number>",
+                chalk.yellowBright("Minimum weight magnitude to use for attaching the transaction to the tangle"),
+                "14")
+            .option("--seed <string>", chalk.yellowBright("81 Tryte seed used to generate addresses (required)"))
+            .option("--address-index <number>", chalk.yellowBright("Index number used to generate addresses"), "0")
+            .option("--transaction-tag <string>", chalk.yellowBright("Tag to apply to the Tangle transaction"),
+                "GITHUB9RELEASE")
+            .option("--comment <string>",
+                chalk.yellowBright("An optional comment to include in the Tangle transaction payload"))
+            .option("--explorer-url <string>", chalk.yellowBright("Url of the explorer to use for exploration link"),
+                "https://utils.iota.org/transaction/:hash")
+            .option("--no-color", chalk.yellowBright("Disable colored output"))
+            .helpOption("--help",
+                chalk.yellowBright("Display help"));
+
+        program.parse(argv);
+        const opts = program.opts();
+
+        console.log(opts);
+
+        display(chalk.green(`GitHub Tangle Release v${version} ${
+            opts.color === false ? "" : emoji.get("rocket")}\n`));
+
+        const envRepo: string[] = env.GITHUB_REPOSITORY ? env.GITHUB_REPOSITORY.split("/") : [];
+
+        if (envRepo.length === 2) {
+            opts.owner = opts.owner || envRepo[0];
+            opts.repository = opts.repository || envRepo[1];
+        }
+
+        const config = sanitizeInput({
+            githubToken: opts.githubToken || env.GITHUB_TOKEN,
+            owner: opts.owner,
+            repository: opts.repository,
+            releaseTag: opts.releaseTag || env.GITHUB_REF,
+            node: opts.node,
+            depth: opts.depth,
+            mwm: opts.mwm,
+            seed: opts.seed || env.GTR_SEED,
+            addressIndex: opts.addressIndex,
+            transactionTag: opts.transactionTag,
+            comment: opts.comment,
+            explorerUrl: opts.explorerUrl
+        });
+
+        display("Options:");
+        display(chalk.cyan("\tGitHub Token"), chalk.white("*******"));
+        display(chalk.cyan("\tOwner"), chalk.white(config.owner));
+        display(chalk.cyan("\tRepository"), chalk.white(config.repository));
+        display(chalk.cyan("\tRelease Tag"), chalk.white(config.releaseTag));
+        display(chalk.cyan("\tNode"), chalk.white(config.node));
+        display(chalk.cyan("\tDepth"), chalk.white(config.depth));
+        display(chalk.cyan("\tMWM"), chalk.white(config.mwm));
+        display(chalk.cyan("\tSeed"), chalk.white("*******"));
+        display(chalk.cyan("\tAddress Index"), chalk.white(config.addressIndex));
+        display(chalk.cyan("\tTransaction Tag"), chalk.white(config.transactionTag));
+        if (config.comment) {
+            display(chalk.cyan("\tComment"), chalk.white(config.comment));
+        }
+        display(chalk.cyan("\tExplorer Url"), chalk.white(config.explorerUrl));
+        display("");
+
+        try {
+            const transactionDetails = await tangleRelease(config, message => display(chalk.green(message)));
+
+            display("Transaction Hash:",
+                chalk.cyan(transactionDetails.hash));
+            display("You can view the transaction on the tangle at:",
+                chalk.cyan(transactionDetails.url));
+            display(chalk.green("Complete"));
+        } catch (err) {
+            display("");
+            display(createErrors(err));
+            process.exit(1);
+        }
+    } catch (err) {
+        program.help(str => `${str}${createEnvHelp()}${createExample()}${createErrors(err)}`);
+        process.exit(1);
+    }
+}
+
+/**
+ * Show an example on the console.
+ * @returns The example text.
+ */
+function createExample(): string {
+    // eslint-disable-next-line max-len
+    return chalk.magenta("\nExample: gh-tangle-release --github-token a4d936470cb3d66f5434f787c2500bde9764f --owner my-org --repository my-repo --release-tag v1.0.1 --seed AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n\n");
+}
+
+/**
+ * Show additional info about env vars.
+ * @returns The additional information.
+ */
+function createEnvHelp(): string {
+    return `
+${chalk.cyan("You can also supply some of the options through environment variables:")}
+   ${chalk.cyan("--github-token: GITHUB_TOKEN")}
+   ${chalk.cyan("--owner: GITHUB_REPOSITORY[0]")}
+   ${chalk.cyan("--repository: GITHUB_REPOSITORY[1]")}
+   ${chalk.cyan("     where GITHUB_REPOSITORY is formatted owner/repository")}
+   ${chalk.cyan("--release-tag: GITHUB_REF")}
+   ${chalk.cyan("--seed: GTR_SEED")}\n\n`;
+}
+
+/**
+ * Show the errors.
+ * @param error The error that was thrown.
+ * @returns The formatted errors.
+ */
+function createErrors(error: Error): string {
+    return chalk.red(`The following errors occurred:\n   ${error.message.replace(/\n/g, "\n   ")}`);
+}
diff --git a/src/cli.ts b/src/cli.ts
index 742118b..e0127b1 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -1,106 +1,10 @@
 #!/usr/bin/env node
-import chalk from "chalk";
-import { Command } from "commander";
-import emoji from "node-emoji";
-import { sanitizeInput, tangleRelease } from "./core";
+import { cliCore } from "./cli-core";
 
-const version = "0.7.0";
-console.log(chalk.green(`GitHub Tangle Release v${version} ${emoji.get("rocket")}\n`));
-
-const program = new Command();
-
-program
-    .storeOptionsAsProperties(false)
-    .passCommandToAction(false);
-
-program
-    .name(chalk.yellowBright("gh-tangle-release"))
-    .version(version, "-v, --version", chalk.yellowBright("output the current version"))
-    .description(chalk.cyan("An application for creating a transaction on the IOTA Tangle from a GitHub release."))
-    .option("--github-token <string>", chalk.yellowBright("GitHub token for accessing your repository (required)"))
-    .option("--owner <string>", chalk.yellowBright("GitHub repository owner (required)"))
-    .option("--repository <string>", chalk.yellowBright("GitHub repository (required)"))
-    .option("--release-tag <string>", chalk.yellowBright("The release tag from the GitHub repository (required)"))
-    .option("--node <string>", chalk.yellowBright("Url of the node to use for attaching the transaction to the tangle"),
-        "https://nodes.iota.cafe:443")
-    .option("--depth <number>", chalk.yellowBright("Depth to use for attaching the transaction to the tangle"),
-        "3")
-    .option("--mwm <number>",
-        chalk.yellowBright("Minimum weight magnitude to use for attaching the transaction to the tangle"),
-        "14")
-    .option("--seed <string>", chalk.yellowBright("81 Tryte seed used to generate addresses (required)"))
-    .option("--address-index <number>", chalk.yellowBright("Index number used to generate addresses"), "0")
-    .option("--transaction-tag <string>", chalk.yellowBright("Tag to apply to the Tangle transaction"), "GITHUB9RELEASE")
-    .option("--comment <string>",
-        chalk.yellowBright("An optional comment to include in the Tangle transaction payload"))
-    .option("--explorer-url <string>", chalk.yellowBright("Url of the explorer to use for exploration link"),
-        "https://utils.iota.org/transaction/:hash")
-    .helpOption("--help",
-        chalk.yellowBright("Display help"));
-
-if (process.argv.length === 2) {
-    program.help(str => `${str}${createExample()}`);
-} else {
-    try {
-        program.parse(process.argv);
-
-        const opts = program.opts();
-
-        const config = sanitizeInput({
-            githubToken: opts.githubToken,
-            owner: opts.owner,
-            repository: opts.repository,
-            releaseTag: opts.releaseTag,
-            node: opts.node,
-            depth: opts.depth,
-            mwm: opts.mwm,
-            seed: opts.seed,
-            // eslint-disable-next-line unicorn/no-null
-            addressIndex: null as unknown as number, // opts.addressIndex,
-            transactionTag: opts.transactionTag,
-            comment: opts.comment,
-            explorerUrl: opts.explorerUrl
-        });
-        console.log("Options:");
-        console.log(chalk.cyan("\tGitHub Token"), chalk.white("*******"));
-        console.log(chalk.cyan("\tOwner"), chalk.white(config.owner));
-        console.log(chalk.cyan("\tRepository"), chalk.white(config.repository));
-        console.log(chalk.cyan("\tRelease Tag"), chalk.white(config.releaseTag));
-        console.log(chalk.cyan("\tNode"), chalk.white(config.node));
-        console.log(chalk.cyan("\tDepth"), chalk.white(config.depth));
-        console.log(chalk.cyan("\tMWM"), chalk.white(config.mwm));
-        console.log(chalk.cyan("\tSeed"), chalk.white("*******"));
-        console.log(chalk.cyan("\tAddress Index"), chalk.white(config.addressIndex));
-        console.log(chalk.cyan("\tTransaction Tag"), chalk.white(config.transactionTag));
-        if (config.comment) {
-            console.log(chalk.cyan("\tComment"), chalk.white(config.comment));
-        }
-        console.log(chalk.cyan("\tExplorer Url"), chalk.white(config.explorerUrl));
-        console.log();
-
-        tangleRelease(config, message => console.log(chalk.green(message)))
-            .then(transactionDetails => {
-                console.log("Transaction Hash:",
-                    chalk.cyan(transactionDetails.hash));
-                console.log("You can view the transaction on the tangle at:",
-                    chalk.cyan(transactionDetails.url));
-                console.log(chalk.green("Complete"));
-            })
-            .catch(err => {
-                console.log();
-                console.error(chalk.red(err));
-                process.exit(1);
-            });
-    } catch (err) {
-        program.help(str => `${str}${chalk.red(`Error: ${err.message}`)}`);
+cliCore(process.argv, process.env, (message, param) => {
+    process.stdout.write(message);
+    if (param) {
+        process.stdout.write(` ${param}`);
     }
-}
-
-/**
- * Show an example on the console.
- * @returns The example text.
- */
-function createExample(): string {
-    // eslint-disable-next-line max-len
-    return chalk.magenta("\nExample: gh-tangle-release --github-token a4d936470cb3d66f5434f787c2500bde9764f --owner my-org --repository my-repo --release-tag v1.0.1 --seed AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n");
-}
+    process.stdout.write("\n");
+}).catch(err => process.stderr.write(err.message));
diff --git a/src/core.ts b/src/core.ts
index 0252da3..32d3e0f 100644
--- a/src/core.ts
+++ b/src/core.ts
@@ -12,35 +12,34 @@ import { IPayload } from "./models/IPayload";
  * @returns The config as non partial.
  */
 export function sanitizeInput(config: IPartialConfig): IConfig {
+    const errors: string[] = [];
     if (!config.githubToken) {
-        throw new Error("You must provide the GitHub token option");
+        errors.push("You must provide the GitHub token option");
     }
     if (!config.owner) {
-        throw new Error("You must provide the owner option");
+        errors.push("You must provide the owner option");
     }
     if (!config.repository) {
-        throw new Error("You must provide the repository option");
+        errors.push("You must provide the repository option");
     }
     if (!config.releaseTag) {
-        throw new Error("You must provide the release tag option");
+        errors.push("You must provide the release tag option");
     }
     if (!config.seed) {
-        throw new Error("You must provide the seed option");
-    }
-    if (!/[9A-Z]/.test(config.seed)) {
-        throw new Error("The seed option must be 81 trytes [A-Z9]");
-    }
-    if (config.seed.length !== 81) {
-        throw new Error(`The seed option must be 81 trytes [A-Z9], it is ${config.seed.length}`);
+        errors.push("You must provide the seed option");
+    } else if (!/[9A-Z]/.test(config.seed)) {
+        errors.push("The seed option must be 81 trytes [A-Z9]");
+    } else if (config.seed.length !== 81) {
+        errors.push(`The seed option must be 81 trytes [A-Z9], it is ${config.seed.length}`);
     }
 
     config.transactionTag = config.transactionTag || "GITHUB9RELEASE";
 
     if (!/[9A-Z]/.test(config.transactionTag)) {
-        throw new Error("The transaction tag option must be 27 trytes [A-Z9] or less");
+        errors.push("The transaction tag option must be 27 trytes [A-Z9] or less");
     }
     if (config.transactionTag.length > 27) {
-        throw new Error(`The transaction tag option must be 27 trytes [A-Z9] or less, it is ${
+        errors.push(`The transaction tag option must be 27 trytes [A-Z9] or less, it is ${
             config.transactionTag.length}`);
     }
 
@@ -75,15 +74,19 @@ export function sanitizeInput(config: IPartialConfig): IConfig {
         mwm = config.mwm;
     }
 
+    if (errors.length > 0) {
+        throw new Error(errors.join("\n"));
+    }
+
     return {
-        githubToken: config.githubToken,
-        owner: config.owner,
-        repository: config.repository,
-        releaseTag: config.releaseTag,
+        githubToken: config.githubToken || "",
+        owner: config.owner || "",
+        repository: config.repository || "",
+        releaseTag: config.releaseTag || "",
         node: config.node,
         depth,
         mwm,
-        seed: config.seed,
+        seed: config.seed || "",
         addressIndex,
         transactionTag: config.transactionTag,
         comment: config.comment,
diff --git a/tests/cli-core.spec.ts b/tests/cli-core.spec.ts
new file mode 100644
index 0000000..438ab1f
--- /dev/null
+++ b/tests/cli-core.spec.ts
@@ -0,0 +1,57 @@
+import chalk from "chalk";
+import { cliCore } from "../src/cli-core";
+
+describe("CLI", () => {
+    let processExitSpy: jest.SpyInstance;
+    let processStdoutWriteSpy: jest.SpyInstance;
+    let output: string[] = [];
+
+    const appendToOutput = (message: string | Uint8Array): void => {
+        output = output.concat(
+            message
+                .toString()
+                .split("\n")
+                .map(s => s.trim())
+        );
+    };
+
+    beforeAll(() => {
+        chalk.level = 0;
+
+        processStdoutWriteSpy = jest.spyOn(process.stdout, "write").mockImplementation(message => {
+            appendToOutput(message);
+            return true;
+        });
+        processExitSpy = jest.spyOn(process, "exit").mockImplementation();
+    });
+
+    afterEach(() => {
+        output = [];
+    });
+
+    afterAll(() => {
+        processStdoutWriteSpy.mockRestore();
+        processExitSpy.mockRestore();
+    });
+
+    test("No Params", async () => {
+        await cliCore([], {}, appendToOutput);
+        expect(processExitSpy).toHaveBeenCalledWith(1);
+        expect(output).toContain("You must provide the GitHub token option");
+        expect(output).toContain("You must provide the owner option");
+        expect(output).toContain("You must provide the repository option");
+        expect(output).toContain("You must provide the release tag option");
+        expect(output).toContain("You must provide the seed option");
+    });
+
+    test("Env Params", async () => {
+        await cliCore([], {
+            GITHUB_TOKEN: "g",
+            GITHUB_REPOSITORY: "o/r",
+            GITHUB_REF: "refs/heads/tag",
+            GTR_SEED: "S".repeat(81)
+        }, appendToOutput);
+        expect(processExitSpy).toHaveBeenCalledWith(1);
+        expect(output).toContain("Bad credentials");
+    });
+});
diff --git a/tests/core.spec.ts b/tests/core.spec.ts
index 8f6918d..5a5e10d 100644
--- a/tests/core.spec.ts
+++ b/tests/core.spec.ts
@@ -2,10 +2,6 @@ import { sanitizeInput } from "../src/core";
 import { IPartialConfig } from "../src/models/IPartialConfig";
 
 describe("Tangle Release", () => {
-    afterEach(() => {
-        jest.clearAllMocks();
-    });
-
     test("No GITHUB_TOKEN", async () => {
         const config: IPartialConfig = {};
         expect(() => sanitizeInput(config)).toThrow("You must provide the GitHub token option");
@@ -45,6 +41,54 @@ describe("Tangle Release", () => {
         expect(() => sanitizeInput(config)).toThrow("You must provide the seed option");
     });
 
+    test("Seed non trytes characters", async () => {
+        const config: IPartialConfig = {
+            githubToken: "aaa",
+            owner: "abc",
+            repository: "repo1/app1",
+            releaseTag: "v1",
+            seed: "aaa"
+        };
+        expect(() => sanitizeInput(config)).toThrow("The seed option must be 81 trytes [A-Z9]");
+    });
+
+    test("Seed wrong length", async () => {
+        const config: IPartialConfig = {
+            githubToken: "aaa",
+            owner: "abc",
+            repository: "repo1/app1",
+            releaseTag: "v1",
+            seed: "AAA"
+        };
+        expect(() => sanitizeInput(config)).toThrow("The seed option must be 81 trytes [A-Z9], it is 3");
+    });
+
+    test("Transaction tag non trytes characters", async () => {
+        const config: IPartialConfig = {
+            githubToken: "aaa",
+            owner: "abc",
+            repository: "repo1/app1",
+            releaseTag: "v1",
+            seed: "A".repeat(81),
+            transactionTag: "a"
+        };
+        expect(() =>
+            sanitizeInput(config)).toThrow("The transaction tag option must be 27 trytes [A-Z9] or less");
+    });
+
+    test("Transaction tag length too long", async () => {
+        const config: IPartialConfig = {
+            githubToken: "aaa",
+            owner: "abc",
+            repository: "repo1/app1",
+            releaseTag: "v1",
+            seed: "A".repeat(81),
+            transactionTag: "A".repeat(28)
+        };
+        expect(() =>
+            sanitizeInput(config)).toThrow("The transaction tag option must be 27 trytes [A-Z9] or less, it is 28");
+    });
+
     test("Sanitized partial input", async () => {
         const config: IPartialConfig = {
             githubToken: "aaa",
@@ -81,7 +125,7 @@ describe("Tangle Release", () => {
             mwm: "2",
             addressIndex: 10,
             explorerUrl: "https://bar",
-            transactionTag: "TAGTAGTAG",
+            transactionTag: "T".repeat(27),
             comment: "Mmmmm"
         };
         expect(sanitizeInput(config)).toEqual({
@@ -95,7 +139,7 @@ describe("Tangle Release", () => {
             mwm: 2,
             explorerUrl: "https://bar",
             seed: "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
-            transactionTag: "TAGTAGTAG",
+            transactionTag: "T".repeat(27),
             comment: "Mmmmm"
         });
     });