diff --git a/examples/repeatable-arg/README.md b/examples/repeatable-arg/README.md
index 547b6689..53920b58 100644
--- a/examples/repeatable-arg/README.md
+++ b/examples/repeatable-arg/README.md
@@ -34,6 +34,9 @@ args:
   # needs to be converted to an array with `eval "data=(${args[file]})"`
   repeatable: true
 
+  # Setting unique to true will ignore non-unique repeating values
+  unique: true
+
 examples:
 - upcase README.md LICENSE
 - upcase *.md
@@ -125,5 +128,23 @@ args:
 
 ````
 
+### `$ ./upcase file1 file2 file1`
+
+````shell
+
+files:
+  path: file1:
+  content: content of file1
+  upcase: CONTENT OF FILE1
+  path: file2:
+  content: content of file2
+  upcase: CONTENT OF FILE2
+
+args:
+- ${args[file]} = "file1" "file2"
+
+
+````
+
 
 
diff --git a/examples/repeatable-arg/src/bashly.yml b/examples/repeatable-arg/src/bashly.yml
index 9c9c0c9e..de60bdec 100644
--- a/examples/repeatable-arg/src/bashly.yml
+++ b/examples/repeatable-arg/src/bashly.yml
@@ -13,6 +13,9 @@ args:
   # needs to be converted to an array with `eval "data=(${args[file]})"`
   repeatable: true
 
+  # Setting unique to true will ignore non-unique repeating values
+  unique: true
+
 examples:
 - upcase README.md LICENSE
 - upcase *.md
diff --git a/examples/repeatable-arg/test.sh b/examples/repeatable-arg/test.sh
index f1ccc9c8..642b243d 100644
--- a/examples/repeatable-arg/test.sh
+++ b/examples/repeatable-arg/test.sh
@@ -9,3 +9,4 @@ bashly generate
 ./upcase -h
 ./upcase file1
 ./upcase file*
+./upcase file1 file2 file1
diff --git a/lib/bashly/config_validator.rb b/lib/bashly/config_validator.rb
index e1fd661b..da55a0c9 100644
--- a/lib/bashly/config_validator.rb
+++ b/lib/bashly/config_validator.rb
@@ -95,12 +95,17 @@ def assert_arg(key, value)
       assert_optional_string "#{key}.validate", value['validate']
       assert_boolean "#{key}.required", value['required']
       assert_boolean "#{key}.repeatable", value['repeatable']
+      assert_boolean "#{key}.unique", value['unique']
 
       assert_array "#{key}.allowed", value['allowed'], of: :string
 
       refute value['name'].match(/^-/), "#{key}.name must not start with '-'"
 
       refute value['required'] && value['default'], "#{key} cannot have both nub`required` and nub`default`"
+
+      if value['unique']
+        assert value['repeatable'], "#{key}.unique does not make sense without nub`repeatable`"
+      end
     end
 
     def assert_flag(key, value)
@@ -143,8 +148,7 @@ def assert_flag(key, value)
       end
 
       if value['unique']
-        condition = value['arg'] && value['repeatable']
-        assert condition, "#{key}.unique does not make sense without nub`arg` and nub`repeatable`"
+        assert value['arg'] && value['repeatable'], "#{key}.unique does not make sense without nub`arg` and nub`repeatable`"
       end
     end
 
diff --git a/lib/bashly/script/argument.rb b/lib/bashly/script/argument.rb
index 0b8aefa9..2e417456 100644
--- a/lib/bashly/script/argument.rb
+++ b/lib/bashly/script/argument.rb
@@ -4,7 +4,7 @@ class Argument < Base
       class << self
         def option_keys
           @option_keys ||= %i[
-            allowed default help name repeatable required validate
+            allowed default help name repeatable required unique validate
           ]
         end
       end
diff --git a/lib/bashly/views/command/parse_requirements_case_repeatable.gtx b/lib/bashly/views/command/parse_requirements_case_repeatable.gtx
index 35d0a4c6..b78484c8 100644
--- a/lib/bashly/views/command/parse_requirements_case_repeatable.gtx
+++ b/lib/bashly/views/command/parse_requirements_case_repeatable.gtx
@@ -7,9 +7,17 @@ args.each do |arg|
   if arg.repeatable
     >   args['{{ arg.name }}']="\"$1\""
     >   shift
-    > else
-    >   args['{{ arg.name }}']="${args[{{ arg.name }}]} \"$1\""
-    >   shift
+    if arg.unique
+      > elif [[ ! "${args['{{ arg.name }}']}" =~ \"$1\" ]]; then
+      >   args['{{ arg.name }}']="${args[{{ arg.name }}]} \"$1\""
+      >   shift
+      > else
+      >   shift
+    else
+      > else
+      >   args['{{ arg.name }}']="${args[{{ arg.name }}]} \"$1\""
+      >   shift
+    end
 
   else
     >   args['{{ arg.name }}']=$1
diff --git a/spec/approvals/examples/repeatable-arg b/spec/approvals/examples/repeatable-arg
index e99745d1..91ca79dc 100644
--- a/spec/approvals/examples/repeatable-arg
+++ b/spec/approvals/examples/repeatable-arg
@@ -47,3 +47,15 @@ files:
 
 args:
 - ${args[file]} = "file1" "file2"
++ ./upcase file1 file2 file1
+
+files:
+  path: file1:
+  content: content of file1
+  upcase: CONTENT OF FILE1
+  path: file2:
+  content: content of file2
+  upcase: CONTENT OF FILE2
+
+args:
+- ${args[file]} = "file1" "file2"
diff --git a/spec/approvals/validations/arg_unique_without_repeatable b/spec/approvals/validations/arg_unique_without_repeatable
new file mode 100644
index 00000000..e1c83442
--- /dev/null
+++ b/spec/approvals/validations/arg_unique_without_repeatable
@@ -0,0 +1 @@
+#<Bashly::ConfigurationError: root.args[0].unique does not make sense without nub`repeatable`>
\ No newline at end of file
diff --git a/spec/fixtures/script/validations.yml b/spec/fixtures/script/validations.yml
index bfedf331..b36d41da 100644
--- a/spec/fixtures/script/validations.yml
+++ b/spec/fixtures/script/validations.yml
@@ -42,6 +42,14 @@
   - name: target
     help: Target filename
 
+:arg_unique_without_repeatable:
+  name: invalid
+  help: arg must be repeatable when using unique
+  args:
+  - name: target
+    help: Target filename
+    unique: true
+
 :command_catch_all_type:
   name: invalid
   help: catch_all must be boolean, string, or hash