[system] List env_var names

Signed-off-by: Pablo Fernández Rodríguez <[email protected]>

sos/report/plugins/system.py

@@ -6,6 +6,7 @@
 #
 # See the LICENSE file in the source distribution for further information.
 
+import os
 from sos.report.plugins import Plugin, IndependentPlugin
 
 
@@ -40,6 +41,12 @@ def setup(self):
             "ld.so --list-tunables"
         ])
 
+        var_names = list(os.environ.keys())
+        var_names.sort()
+        self.add_string_as_file('\n'.join(var_names),
+                                "environment_varnames",
+                                plug_dir=True)
+
     def postproc(self):
         self.do_paths_http_sub([
             "/etc/sysconfig",