diff --git a/README.md b/README.md
index 3e25ba1..73d23a2 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ These formats are supported for now: `http`, `curl`, `wget`.
 - tests, phpcs, psalm, etc.;
 - web version.
 
-## Installation
+## Install and upgrade
 
 ```
 composer global r axenov/pm-convert
diff --git a/composer.json b/composer.json
index 4a1b864..d144c19 100644
--- a/composer.json
+++ b/composer.json
@@ -1,7 +1,7 @@
 {
     "name": "axenov/pm-convert",
     "type": "library",
-    "description": "Postman collection coverter",
+    "description": "Postman collection converter",
     "license": "MIT",
     "homepage": "https://axenov.dev/",
     "authors": [
diff --git a/src/Exporters/Abstract/AbstractConverter.php b/src/Exporters/Abstract/AbstractConverter.php
index 8115ea8..46cb256 100644
--- a/src/Exporters/Abstract/AbstractConverter.php
+++ b/src/Exporters/Abstract/AbstractConverter.php
@@ -32,9 +32,9 @@ abstract class AbstractConverter implements ConverterContract
     protected array $vars = [];
 
     /**
-     * @var Environment
+     * @var Environment|null
      */
-    protected Environment $env;
+    protected ?Environment $env = null;
 
     /**
      * Sets an environment with vars
@@ -173,11 +173,11 @@ abstract class AbstractConverter implements ConverterContract
      */
     protected function interpolate(string $content): string
     {
-        if (empty($this->vars) && !empty($this->env) && $this->env->hasVars()) {
+        if (empty($this->vars) && !$this->env?->hasVars()) {
             return $content;
         }
         $matches = [];
-        if (preg_match_all('/\{\{[a-zA-Z][a-zA-Z0-9]+}}/', $content, $matches, PREG_PATTERN_ORDER) > 0) {
+        if (preg_match_all('/\{\{[a-zA-Z][a-zA-Z0-9]*}}/m', $content, $matches, PREG_PATTERN_ORDER) > 0) {
             foreach ($matches[0] as $key => $var) {
                 if (str_contains($content, $var)) {
                     $content = str_replace($var, $this->vars[$var] ?? $this->env[$var] ?? $var, $content);
diff --git a/src/Processor.php b/src/Processor.php
index 9bb8cb2..1e15f79 100644
--- a/src/Processor.php
+++ b/src/Processor.php
@@ -7,22 +7,21 @@ namespace PmConverter;
 use Exception;
 use InvalidArgumentException;
 use JsonException;
-use PmConverter\Exceptions\CannotCreateDirectoryException;
-use PmConverter\Exceptions\DirectoryIsNotReadableException;
-use PmConverter\Exceptions\DirectoryIsNotWriteableException;
-use PmConverter\Exceptions\DirectoryNotExistsException;
-use PmConverter\Exporters\ConverterContract;
-use PmConverter\Exporters\ConvertFormat;
+use PmConverter\Exceptions\{
+    CannotCreateDirectoryException,
+    DirectoryIsNotReadableException,
+    DirectoryIsNotWriteableException,
+    DirectoryNotExistsException};
+use PmConverter\Exporters\{
+    ConverterContract,
+    ConvertFormat};
 
-/**
- *
- */
 class Processor
 {
     /**
      * Converter version
      */
-    public const VERSION = '1.2.3';
+    public const VERSION = '1.2.4';
 
     /**
      * @var string[] Paths to collection files
@@ -89,9 +88,6 @@ class Processor
      * Parses an array of arguments came from cli
      *
      * @return void
-     * @throws DirectoryIsNotWriteableException
-     * @throws DirectoryNotExistsException
-     * @throws DirectoryIsNotReadableException
      */
     protected function parseArgs(): void
     {
@@ -285,7 +281,7 @@ class Processor
     {
         $time = (hrtime(true) - $this->initTime) / 1_000_000;
         $ram = (memory_get_peak_usage(true) - $this->initRam) / 1024 / 1024;
-        printf('Converted %d of %d in %.3f ms using %.3f MiB RAM', $success, $count, $time, $ram);
+        printf('Converted %d of %d in %.3f ms using %.3f MiB RAM%s', $success, $count, $time, $ram, PHP_EOL);
     }
 
     /**
@@ -321,7 +317,7 @@ class Processor
             '',
             'Possible ARGUMENTS:',
             "\t-f, --file       - a PATH to single collection located in PATH to convert from",
-            "\t-d, --dir        - a directory with collections located in COLLECTION_FILEPATH to convert from",
+            "\t-d, --dir        - a directory with collections located in PATH to convert from",
             "\t-o, --output     - a directory OUTPUT_PATH to put results in",
             "\t-e, --env        - use environment file with variable values to replace in request",
             "\t-p, --preserve   - do not delete OUTPUT_PATH (if exists)",
@@ -341,6 +337,7 @@ class Processor
             "\t--http   - generate raw *.http files (default)",
             "\t--curl   - generate shell scripts with curl command",
             "\t--wget   - generate shell scripts with wget command",
+            '',
             'If no FORMATS specified then --http implied.',
             'Any of FORMATS can be specified at the same time.',
             '',