diff --git a/var/spack/repos/builtin/packages/ninja/package.py b/var/spack/repos/builtin/packages/ninja/package.py
index 9e6bf4e358d..0722dd49a64 100644
--- a/var/spack/repos/builtin/packages/ninja/package.py
+++ b/var/spack/repos/builtin/packages/ninja/package.py
@@ -16,7 +16,7 @@ def install(self, spec, prefix):
 
         cp = which('cp')
 
-        bindir = os.path.join(prefix, 'bin')
+        bindir = os.path.join(prefix, 'bin/')
         mkdir(bindir)
-        cp('-a', '-t', bindir, 'ninja')
-        cp('-ra', 'misc', prefix)
+        cp('-a', 'ninja', bindir)
+        cp('-a', 'misc', prefix)