diff --git a/README.md b/README.md
index 6eb8efb..96f5c7a 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,9 @@ pnpm build
 
 # Filter by partial match (case-insensitive)
 ./dist/cli.js --filter API
+./dist/cli.js -f API
 ./dist/cli.js --filter database
+./dist/cli.js -f database
 
 # Display help
 ./dist/cli.js --help
diff --git a/src/cli/config.ts b/src/cli/config.ts
index b1a95b1..4f43ea2 100644
--- a/src/cli/config.ts
+++ b/src/cli/config.ts
@@ -30,7 +30,7 @@ function formatHelpText(): string {
     'Options:',
     '  -h, --help         display help for command',
     '  -v, --version      display version number',
-    '  --filter TEXT      filter variables containing TEXT (case-insensitive)',
+    '  -f, --filter TEXT  filter variables containing TEXT (case-insensitive)',
     '',
     CLI_MESSAGES.HELP_EXAMPLES,
     CLI_MESSAGES.HELP_DESCRIPTION,
diff --git a/src/constants/cli.ts b/src/constants/cli.ts
index 22d7463..c7965f3 100644
--- a/src/constants/cli.ts
+++ b/src/constants/cli.ts
@@ -5,6 +5,7 @@ export const OPTION_ALIASES: Record<string, string> = {
   h: 'help',
   v: 'version',
   V: 'version',
+  f: 'filter',
 };
 
 /**
@@ -18,7 +19,7 @@ export const EXIT_CODES = {
   SUCCESS: 0,
   SYSTEM_ERROR: 1,
   DATA_NOT_FOUND: 2,
-  INVALID_ARGUMENT: 2, // UNIX convention: invalid argument uses exit code 2
+  INVALID_ARGUMENT: 2,
 } as const;
 
 export type ExitCode = (typeof EXIT_CODES)[keyof typeof EXIT_CODES];
diff --git a/src/core/filter.ts b/src/core/filter.ts
index 9f2dd23..6c7ca73 100644
--- a/src/core/filter.ts
+++ b/src/core/filter.ts
@@ -1,30 +1,44 @@
 import type { EnvironmentData, FilterConfig, FilterResult } from '../types/environment.js';
 import { ERROR_MESSAGES, CLI_MESSAGES } from '../constants/index.js';
 
+/**
+ * Creates a filter function that matches environment variables by type and search text
+ * @param type - The type of filter ('prefix' or 'partial')
+ * @param searchText - The text to match (case-insensitive)
+ * @returns A filter function that checks if a variable matches the criteria
+ */
+export function createFilter(
+  type: 'prefix' | 'partial',
+  searchText: string,
+): (env: EnvironmentData) => boolean {
+  const lowerSearchText = searchText.toLowerCase();
+
+  return (env: EnvironmentData): boolean => {
+    const lowerKey = env.key.toLowerCase();
+    return type === 'prefix'
+      ? lowerKey.startsWith(lowerSearchText)
+      : lowerKey.includes(lowerSearchText);
+  };
+}
+
 /**
  * Creates a filter function that matches environment variables by prefix
  * @param prefix - The prefix to match (case-insensitive)
  * @returns A filter function that checks if a variable starts with the prefix
+ * @deprecated Use createFilter('prefix', prefix) instead
  */
 export function createPrefixFilter(prefix: string): (env: EnvironmentData) => boolean {
-  const lowerPrefix = prefix.toLowerCase();
-
-  return (env: EnvironmentData): boolean => {
-    return env.key.toLowerCase().startsWith(lowerPrefix);
-  };
+  return createFilter('prefix', prefix);
 }
 
 /**
  * Creates a filter function that matches environment variables by partial match
  * @param searchText - The text to search for (case-insensitive)
  * @returns A filter function that checks if a variable contains the search text
+ * @deprecated Use createFilter('partial', searchText) instead
  */
 export function createPartialMatchFilter(searchText: string): (env: EnvironmentData) => boolean {
-  const lowerSearchText = searchText.toLowerCase();
-
-  return (env: EnvironmentData): boolean => {
-    return env.key.toLowerCase().includes(lowerSearchText);
-  };
+  return createFilter('partial', searchText);
 }
 
 /**
@@ -50,14 +64,7 @@ export function filterEnvironmentVariables(
   }
 
   // Apply appropriate filter based on type
-  let filter: (env: EnvironmentData) => boolean;
-
-  if (config.type === 'prefix') {
-    filter = createPrefixFilter(config.value);
-  } else {
-    // config.type === 'partial'
-    filter = createPartialMatchFilter(config.value);
-  }
+  const filter = createFilter(config.type, config.value);
 
   const filtered = data.filter(filter);
 
diff --git a/tests/unit/cli/parser.test.ts b/tests/unit/cli/parser.test.ts
index 82ebd0f..77d5bc9 100644
--- a/tests/unit/cli/parser.test.ts
+++ b/tests/unit/cli/parser.test.ts
@@ -241,6 +241,37 @@ describe('CLI Parser', () => {
         expect(result.data.arguments).toEqual(['PREFIX']);
       }
     });
+
+    it('should parse -f option with value', () => {
+      const result = parseArgs(['node', 'cli.js', '-f', 'API'], mockConfig);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.command).toBe('main');
+        expect(result.data.flags.has('filter')).toBe(true);
+        expect(result.data.filterValue).toBe('API');
+        expect(result.data.arguments).toEqual([]);
+      }
+    });
+
+    it('should handle -f without value', () => {
+      const result = parseArgs(['node', 'cli.js', '-f'], mockConfig);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.type).toBe('filter_requires_value');
+        expect(result.error.message).toBe('--filter option requires a search text');
+      }
+    });
+
+    it('should trim whitespace from -f value', () => {
+      const result = parseArgs(['node', 'cli.js', '-f', '  API  '], mockConfig);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.filterValue).toBe('API');
+      }
+    });
   });
 
   describe('isValidOption', () => {