Make sed expressions safe to run multiple times

Also, make them ignore commented lines.

diff --git a/teuthology/task/internal.py b/teuthology/task/internal.py
index 9541c07b16d78dc0151f95f72a2a13571e21e8f5..30d48075641de35e2f9e3879db2dde296f1ca7ab 100644 (file)
--- a/teuthology/task/internal.py
+++ b/teuthology/task/internal.py
@@ -288,8 +288,8 @@ def sudo(ctx, config):
     log.info('Configuring sudo...')
     sudoers_file = '/etc/sudoers'
     backup_ext = '.orig.teuthology'
-    tty_expr = 's/requiretty/!requiretty/'
-    pw_expr = 's/!visiblepw/visiblepw/'
+    tty_expr = 's/^\([^#]*\) \(requiretty\)/\1 !\2/g'
+    pw_expr = 's/^\([^#]*\) !\(visiblepw\)/\1 \2/g'
 
     run.wait(
         ctx.cluster.run(