1 files changed, 35 insertions, 4 deletions
diff --git a/lib/spack/spack/hooks/sbang.py b/lib/spack/spack/hooks/sbang.py
index b4ee0c1728..324d5d4fbb 100644
--- a/lib/spack/spack/hooks/sbang.py
+++ b/lib/spack/spack/hooks/sbang.py
@@ -3,21 +3,30 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
+import filecmp
 import os
 import stat
 import re
 import sys
 
 import llnl.util.tty as tty
+import llnl.util.filesystem as fs
 
-import spack.paths
 import spack.modules
+import spack.paths
+import spack.store
+
 
-# Character limit for shebang line.  Using Linux's 127 characters
-# here, as it is the shortest I could find on a modern OS.
+#: Character limit for shebang line.  Using Linux's 127 characters
+#: here, as it is the shortest I could find on a modern OS.
 shebang_limit = 127
 
 
+def sbang_install_path():
+    """Location sbang should be installed within Spack's ``install_tree``."""
+    return os.path.join(spack.store.layout.root, "bin", "sbang")
+
+
 def shebang_too_long(path):
     """Detects whether a file has a shebang line that is too long."""
     if not os.path.isfile(path):
@@ -42,7 +51,7 @@ def filter_shebang(path):
             original = original.decode('UTF-8')
 
     # This line will be prepended to file
-    new_sbang_line = '#!/bin/bash %s/bin/sbang\n' % spack.paths.prefix
+    new_sbang_line = '#!/bin/bash %s\n' % sbang_install_path()
 
     # Skip files that are already using sbang.
     if original.startswith(new_sbang_line):
@@ -102,6 +111,26 @@ def filter_shebangs_in_directory(directory, filenames=None):
             filter_shebang(path)
 
 
+def install_sbang():
+    """Ensure that ``sbang`` is installed in the root of Spack's install_tree.
+
+    This is the shortest known publicly accessible path, and installing
+    ``sbang`` here ensures that users can access the script and that
+    ``sbang`` itself is in a short path.
+    """
+    # copy in a new version of sbang if it differs from what's in spack
+    sbang_path = sbang_install_path()
+    if os.path.exists(sbang_path) and filecmp.cmp(
+            spack.paths.sbang_script, sbang_path):
+        return
+
+    # make $install_tree/bin and copy in a new version of sbang if needed
+    sbang_bin_dir = os.path.dirname(sbang_path)
+    fs.mkdirp(sbang_bin_dir)
+    fs.install(spack.paths.sbang_script, sbang_path)
+    fs.set_install_permissions(sbang_bin_dir)
+
+
 def post_install(spec):
     """This hook edits scripts so that they call /bin/bash
     $spack_prefix/bin/sbang instead of something longer than the
@@ -111,5 +140,7 @@ def post_install(spec):
         tty.debug('SKIP: shebang filtering [external package]')
         return
 
+    install_sbang()
+
     for directory, _, filenames in os.walk(spec.prefix):
         filter_shebangs_in_directory(directory, filenames)