diff --git a/README.md b/README.md
index 372e1da..76f221d 100644
--- a/README.md
+++ b/README.md
@@ -17,3 +17,11 @@ cq ".people.alice.age" < file.cbor
 json-to-cbor < file.json > file.cbor
 ```
 
+# hs usage
+
+`hs` stands for `hexstring`.
+
+```sh
+hs < file.cbor
+```
+
diff --git a/shard.yml b/shard.yml
index 31fa886..fe1de54 100644
--- a/shard.yml
+++ b/shard.yml
@@ -12,6 +12,8 @@ targets:
     main: src/cq.cr
   json-to-cbor:
     main: src/json-to-cbor.cr
+  hs:
+    main: src/hs.cr
   bm-json-vs-cbor:
     main: tests/json-vs-cbor.cr
 
diff --git a/src/hs.cr b/src/hs.cr
new file mode 100644
index 0000000..f54cc73
--- /dev/null
+++ b/src/hs.cr
@@ -0,0 +1,6 @@
+if ARGV.size >= 1
+	puts "usage: hs < file.cbor"
+	exit 0
+end
+
+puts STDIN.gets_to_end.to_slice.hexstring