diff --git a/builder.py b/builder.py
index 71d539d..15ec1fa 100644
--- a/builder.py
+++ b/builder.py
@@ -73,6 +73,9 @@ def _build(t):
             ]
     if vars.VERBOSE:
         argv[1] += 'v'
+    if vars.XTRACE:
+        argv[1] += 'x'
+    if vars.VERBOSE or vars.XTRACE:
         log_('\n')
     log('%s\n' % _nice(t))
     rv = subprocess.call(argv, preexec_fn=lambda: _preexec(t),
@@ -92,7 +95,7 @@ def _build(t):
     f.close()
     if rv != 0:
         raise BuildError('%s: exit code %d' % (t,rv))
-    if vars.VERBOSE:
+    if vars.VERBOSE or vars.XTRACE:
         log('%s (done)\n\n' % _nice(t))
 
 
diff --git a/redo.py b/redo.py
index 86874af..b13df5a 100755
--- a/redo.py
+++ b/redo.py
@@ -7,7 +7,8 @@ redo [targets...]
 --
 j,jobs=    maximum number of jobs to build at once
 d,debug    print dependency checks as they happen
-v,verbose  print commands as they are run
+v,verbose  print commands as they are read from .do files (variables intact)
+x,xtrace   print commands as they are executed (variables expanded)
 shuffle    randomize the build order to find dependency bugs
 debug-locks  print messages about file locking (useful for debugging)
 """
@@ -20,6 +21,8 @@ if opt.debug:
     os.environ['REDO_DEBUG'] = str(opt.debug or 0)
 if opt.verbose:
     os.environ['REDO_VERBOSE'] = '1'
+if opt.xtrace:
+    os.environ['REDO_XTRACE'] = '1'
 if opt.shuffle:
     os.environ['REDO_SHUFFLE'] = '1'
 if opt.debug_locks:
diff --git a/vars.py b/vars.py
index 9c0b888..191a0da 100644
--- a/vars.py
+++ b/vars.py
@@ -7,6 +7,7 @@ DEPTH = os.environ.get('REDO_DEPTH', '')
 DEBUG = atoi.atoi(os.environ.get('REDO_DEBUG', ''))
 DEBUG_LOCKS = os.environ.get('REDO_DEBUG_LOCKS', '') and 1 or 0
 VERBOSE = os.environ.get('REDO_VERBOSE', '') and 1 or 0
+XTRACE = os.environ.get('REDO_XTRACE', '') and 1 or 0
 SHUFFLE = os.environ.get('REDO_SHUFFLE', '') and 1 or 0
 STARTDIR = os.environ['REDO_STARTDIR']
 BASE = os.environ['REDO_BASE']