diff --git a/README.md b/README.md
index 9bc0c14..01754a4 100644
--- a/README.md
+++ b/README.md
@@ -91,8 +91,12 @@ wt
 
 # 15. Print every line with the first field replaced by the line number
 # { $1 = NR; print }
-# Need a way to write value into an index.
-# .. (dup w 1 w w) each
+wt 1 lineNum!
+(
+    @lineNum str 0 setAt
+    " " join wl
+    @lineNum 1 + lineNum!
+) each
 
 # 16. Print every line after erasing the second field
 # { $2 = ""; print }
diff --git a/examples/awk/15.awk b/examples/awk/15.awk
new file mode 100644
index 0000000..f51170a
--- /dev/null
+++ b/examples/awk/15.awk
@@ -0,0 +1 @@
+{ $1 = NR; print }
diff --git a/examples/awk/15.msh b/examples/awk/15.msh
new file mode 100644
index 0000000..72a9179
--- /dev/null
+++ b/examples/awk/15.msh
@@ -0,0 +1,6 @@
+wt 1 lineNum!
+(
+    @lineNum str 0 setAt
+    " " join wl
+    @lineNum 1 + lineNum!
+) each
diff --git a/examples/awk/test.sh b/examples/awk/test.sh
index 550809e..be9a432 100755
--- a/examples/awk/test.sh
+++ b/examples/awk/test.sh
@@ -41,5 +41,6 @@ data_test 11
 emp_test 12
 emp_test 13
 emp_test 14
+emp_test 15
 
 exit "$FAIL"