Add useful merkle-tree bash function

1 files changed, 9 insertions, 0 deletions

diff --git a/bash/util.sh b/bash/util.sh
index b0db4ad..dfdfc12 100644
--- a/bash/util.sh
+++ b/bash/util.sh
@@ -21,3 +21,12 @@ extract () {
         echo "'$1' is not a valid file!"
     fi
 }
+
+merkle-tree () {
+  dirname="${1-.}"
+  find "$dirname" -type f | \ # get all files in the $dirname tree
+    sort                  | \ # sort them to get the same result on different filesystems
+    xargs sha256sum       | \ # compute the SHA256 of each file, BONUS it outputs the filename, so if the content does not change but the filename does, the end hash will be different
+    sha256sum             | \ # compute the final hash
+    awk '{print $1}'          # omit the filename, which is `-` as stdin in this case
+}