2 files changed, 10 insertions, 0 deletions
diff --git a/README.md b/README.md
index 4889909..8b9252d 100644
--- a/README.md
+++ b/README.md
@@ -1147,5 +1147,12 @@ Rootly Powers and Processes
   ```
 
   c. Find any sets of entries that have duplicate UIDs.
+
+  ```bash
+  #!/bin/bash
+
+  cat /etc/passwd | grep -v -E '^#' | awk -F: '{ print $3 }' | sort -n | uniq -d
+  ```
+
   d. Find entries that have duplicate login names.
   e. Find entries that have no expiration date (needs /etc/shadow).
diff --git a/bin/duplicate-ids b/bin/duplicate-ids
new file mode 100755
index 0000000..2d04668
--- /dev/null
+++ b/bin/duplicate-ids
@@ -0,0 +1,3 @@
+#!/bin/bash
+
+cat /etc/passwd | grep -v -E '^#'  | awk -F: '{ print $3 }' | sort -n | uniq -d