diff --git a/slides.txt b/slides.txt
index 60b7524..36a6c2f 100644
--- a/slides.txt
+++ b/slides.txt
@@ -286,6 +286,11 @@
 @last
    awk '$NF > 4'              # print lines where last field is more than 4
 
+@last
+.
+   # convert a tab-separated file to a comma-separated file
+   awk 'BEGIN { FS="\t"; OFS="," } {$1=$1; print}' file.tsv > file.csv
+
 @last
 .
    # print number of lines matching 'Foo'