1 files changed, 4 insertions, 1 deletions
diff --git a/TODOs.md b/TODOs.md
index 450d214..9828c1d 100644
--- a/TODOs.md
+++ b/TODOs.md
@@ -1,12 +1,15 @@
 # Tasks
 
-## TODO Is tac POSIX {#task-98478c0f-97ac-4667-acdc-9373e2841de9}
+## DONE Is tac POSIX {#task-98478c0f-97ac-4667-acdc-9373e2841de9}
+- DONE in 2021-01-26
 - TODO in 2021-01-26
 
 ---
 
 If it isn't, what to replace it with?
 
+With [sed](https://unix.stackexchange.com/questions/280685/reverse-sequence-of-a-file-with-posix-tools/280686#comment601716_280686).
+
 ## DONE Add CHANGELOG.md for 0.1.0 {#task-f4258dc4-22aa-408d-a0b1-953f654e0623}
 - DONE in 2021-01-26
 - TODO in 2021-01-24