diff --git a/var/spack/repos/builtin/packages/cmake/package.py b/var/spack/repos/builtin/packages/cmake/package.py
index da94de8dd75..d8b4eefff44 100644
--- a/var/spack/repos/builtin/packages/cmake/package.py
+++ b/var/spack/repos/builtin/packages/cmake/package.py
@@ -44,7 +44,7 @@ class Cmake(Package):
 
     variant('curl',    default=True,  description='Build external curl library')
     variant('expat',   default=True,  description='Build external expat library')
-    # variant('jsoncpp', default=True,  description='Build external jsoncpp library')
+    # variant('jsoncpp', default=True, description='Build external jsoncpp library')  # NOQA: ignore=E501
     variant('zlib',    default=True,  description='Build external zlib library')
     variant('bzip2',   default=True,  description='Build external bzip2 library')
     variant('xz',      default=True,  description='Build external lzma library')
@@ -88,7 +88,7 @@ def install(self, spec, prefix):
         # Consistency check
         self.validate(spec)
 
-	def variant_to_bool(variant):
+        def variant_to_bool(variant):
             return 'system' if variant in spec else 'no-system'
 
         # configure, build, install:
diff --git a/var/spack/repos/builtin/packages/libarchive/package.py b/var/spack/repos/builtin/packages/libarchive/package.py
index 2397075d42b..387af47b26c 100644
--- a/var/spack/repos/builtin/packages/libarchive/package.py
+++ b/var/spack/repos/builtin/packages/libarchive/package.py
@@ -77,6 +77,7 @@ def variant_to_bool(variant):
         ]
 
         configure(*config_args)
+
         make()
-        # make("check")  # cannot build test suite with Intel compilers
-        make("install")
+        # make('check')  # cannot build test suite with Intel compilers
+        make('install')
diff --git a/var/spack/repos/builtin/packages/libxml2/package.py b/var/spack/repos/builtin/packages/libxml2/package.py
index 214a0278052..6b25097bcd6 100644
--- a/var/spack/repos/builtin/packages/libxml2/package.py
+++ b/var/spack/repos/builtin/packages/libxml2/package.py
@@ -45,14 +45,15 @@ class Libxml2(Package):
 
     def install(self, spec, prefix):
         if '+python' in spec:
-            python_args = ["--with-python=%s" % spec['python'].prefix,
-                           "--with-python-install-dir=%s" % site_packages_dir]
+            python_args = [
+                '--with-python={0}'.format(spec['python'].prefix),
+                '--with-python-install-dir={0}'.format(site_packages_dir)
+            ]
         else:
-            python_args = ["--without-python"]
+            python_args = ['--without-python']
 
-        configure("--prefix=%s" % prefix,
-                  *python_args)
+        configure('--prefix={0}'.format(prefix), *python_args)
 
         make()
-        make("check")
-        make("install")
+        make('check')
+        make('install')
diff --git a/var/spack/repos/builtin/packages/nettle/package.py b/var/spack/repos/builtin/packages/nettle/package.py
index 52644fa8a4f..bf494236051 100644
--- a/var/spack/repos/builtin/packages/nettle/package.py
+++ b/var/spack/repos/builtin/packages/nettle/package.py
@@ -38,7 +38,8 @@ class Nettle(Package):
     depends_on('gmp')
 
     def install(self, spec, prefix):
-        configure("--prefix=%s" % prefix)
+        configure('--prefix={0}'.format(prefix))
+
         make()
-        make("check")
-        make("install")
+        make('check')
+        make('install')
diff --git a/var/spack/repos/builtin/packages/xz/package.py b/var/spack/repos/builtin/packages/xz/package.py
index 5b46e838ed7..815d8985041 100644
--- a/var/spack/repos/builtin/packages/xz/package.py
+++ b/var/spack/repos/builtin/packages/xz/package.py
@@ -37,7 +37,8 @@ class Xz(Package):
     version('5.2.2', 'f90c9a0c8b259aee2234c4e0d7fd70af')
 
     def install(self, spec, prefix):
-        configure("--prefix=%s" % prefix)
+        configure('--prefix={0}'.format(prefix))
+
         make()
-        make("check")
-        make("install")
+        make('check')
+        make('install')
diff --git a/var/spack/repos/builtin/packages/zlib/package.py b/var/spack/repos/builtin/packages/zlib/package.py
index 7145b78d634..8834a058043 100644
--- a/var/spack/repos/builtin/packages/zlib/package.py
+++ b/var/spack/repos/builtin/packages/zlib/package.py
@@ -35,8 +35,8 @@ class Zlib(Package):
     version('1.2.8', '44d667c142d7cda120332623eab69f40')
 
     def install(self, spec, prefix):
-        configure("--prefix=%s" % prefix)
+        configure('--prefix={0}'.format(prefix))
 
         make()
-        make("test")
-        make("install")
+        make('test')
+        make('install')