kmx.io/rbpkg

diff --git a/lib/rbpkg.rb b/lib/rbpkg.rb
index e9017c8..d0aca78 100644
--- a/lib/rbpkg.rb
+++ b/lib/rbpkg.rb
@@ -420,10 +420,10 @@ EOF
 
   @@sha256 = nil
   def self.sha256
-    @@sha256 || @@sha256 = if system("which sha256 >/dev/null 2>&1")
-                             "sha256"
-                           elsif system("which sha256sum >/dev/null 2>&1")
+    @@sha256 || @@sha256 = if system("which sha256sum >/dev/null 2>&1")
                              "sha256sum"
+                           elsif system("which sha256 >/dev/null 2>&1")
+                             "sha256"
                            else
                              raise "sha256 executable not found"
                            end
diff --git a/lib/rbpkg/repo.rb b/lib/rbpkg/repo.rb
index e171a85..7e6473e 100644
--- a/lib/rbpkg/repo.rb
+++ b/lib/rbpkg/repo.rb
@@ -457,7 +457,7 @@ class Rbpkg::Repo
             file = scan[1]
             hash = scan[2]
             path = "#{Rbpkg.prefix}/#{file}"
-            `echo 'SHA256 (#{sh_quote(path)}) = #{sh_quote(hash)}' | #{Rbpkg.sha256} -c`
+            `echo 'SHA256 (#{sh_quote(path)}) = #{sh_quote(hash)}' | #{Rbpkg.sha256} -c /dev/stdin`
             if $?.success?
               cmd! "rm #{sh_quote(path)}"
             end