diff --git a/c/reg_test/expected/out b/c/reg_test/expected/out
index af323263e..a002f81bf 100644
--- a/c/reg_test/expected/out
+++ b/c/reg_test/expected/out
@@ -27549,6 +27549,57 @@ n=2,1=abi:zeewye8
 n=3,1=abi:zeepan6
 n=4,1=abi:zeewye8
 
+mlr put -q printn > "./output/printn1/out.".$a, "abi:".$a.$b.$i ./reg_test/input/abixy
+
+mlr cat -n ./output/printn1/out.eks
+n=1,1=abi:ekspan2abi:ekswye4abi:ekszee7
+
+mlr cat -n ./output/printn1/out.hat
+n=1,1=abi:hatwye9
+
+mlr cat -n ./output/printn1/out.pan
+n=1,1=abi:panpan1abi:panwye10
+
+mlr cat -n ./output/printn1/out.wye
+n=1,1=abi:wyewye3abi:wyepan5
+
+mlr cat -n ./output/printn1/out.zee
+n=1,1=abi:zeepan6abi:zeewye8
+
+mlr put -q printn > "./output/printn1/out.".$a, "abi:".$a.$b.$i ./reg_test/input/abixy
+
+mlr cat -n ./output/printn1/out.eks
+n=1,1=abi:ekspan2abi:ekswye4abi:ekszee7
+
+mlr cat -n ./output/printn1/out.hat
+n=1,1=abi:hatwye9
+
+mlr cat -n ./output/printn1/out.pan
+n=1,1=abi:panpan1abi:panwye10
+
+mlr cat -n ./output/printn1/out.wye
+n=1,1=abi:wyewye3abi:wyepan5
+
+mlr cat -n ./output/printn1/out.zee
+n=1,1=abi:zeepan6abi:zeewye8
+
+mlr put -q printn >> "./output/printn1/out.".$a, "abi:".$a.$b.$i ./reg_test/input/abixy
+
+mlr cat -n ./output/printn1/out.eks
+n=1,1=abi:ekspan2abi:ekswye4abi:ekszee7abi:ekspan2abi:ekswye4abi:ekszee7
+
+mlr cat -n ./output/printn1/out.hat
+n=1,1=abi:hatwye9abi:hatwye9
+
+mlr cat -n ./output/printn1/out.pan
+n=1,1=abi:panpan1abi:panwye10abi:panpan1abi:panwye10
+
+mlr cat -n ./output/printn1/out.wye
+n=1,1=abi:wyewye3abi:wyepan5abi:wyewye3abi:wyepan5
+
+mlr cat -n ./output/printn1/out.zee
+n=1,1=abi:zeepan6abi:zeewye8abi:zeepan6abi:zeewye8
+
 
 ================================================================
 DSL DUMP
diff --git a/c/reg_test/run b/c/reg_test/run
index 03bc926d5..e9855ab11 100755
--- a/c/reg_test/run
+++ b/c/reg_test/run
@@ -3495,6 +3495,33 @@ run_mlr cat -n $print1/out.pan
 run_mlr cat -n $print1/out.wye
 run_mlr cat -n $print1/out.zee
 
+# ----------------------------------------------------------------
+announce DSL PRINTN
+
+printn1=$reloutdir/printn1
+mkdir -p $printn1
+
+run_mlr put -q 'printn > "'$printn1'/out.".$a, "abi:".$a.$b.$i' $indir/abixy
+run_mlr cat -n $printn1/out.eks
+run_mlr cat -n $printn1/out.hat
+run_mlr cat -n $printn1/out.pan
+run_mlr cat -n $printn1/out.wye
+run_mlr cat -n $printn1/out.zee
+
+run_mlr put -q 'printn > "'$printn1'/out.".$a, "abi:".$a.$b.$i' $indir/abixy
+run_mlr cat -n $printn1/out.eks
+run_mlr cat -n $printn1/out.hat
+run_mlr cat -n $printn1/out.pan
+run_mlr cat -n $printn1/out.wye
+run_mlr cat -n $printn1/out.zee
+
+run_mlr put -q 'printn >> "'$printn1'/out.".$a, "abi:".$a.$b.$i' $indir/abixy
+run_mlr cat -n $printn1/out.eks
+run_mlr cat -n $printn1/out.hat
+run_mlr cat -n $printn1/out.pan
+run_mlr cat -n $printn1/out.wye
+run_mlr cat -n $printn1/out.zee
+
 # ----------------------------------------------------------------
 announce DSL DUMP
 
diff --git a/c/todo.txt b/c/todo.txt
index c6d575259..193262b84 100644
--- a/c/todo.txt
+++ b/c/todo.txt
@@ -30,6 +30,9 @@ TOP OF LIST:
 UT:
 * cat -> logcat in regtest/run
 * output dir move data off from code !!
+* popen cases
+* non-lashed cases
+* check m*y for any more cases
 
 COMMON:
 * mlr -k needs >/>>/| examples incl. stdout/stderr/file/cmd. also some subset at mlr put -h.