diff --git a/AVsitter2/Makefile b/AVsitter2/Makefile
index 2234ba8..fae0ddf 100644
--- a/AVsitter2/Makefile
+++ b/AVsitter2/Makefile
@@ -15,9 +15,6 @@ PREPROC_KIND=mcpp
 # If the preprocessor is mcpp and it is in your path, you can leave it as is.
 PREPROC_PATH=mcpp
 
-# Command to remove files in your system. Use 'del' for Windows.
-RM=rm -f
-
 # Name of the zipped file to generate for SL
 SLZIP=AVsitter2.zip
 
@@ -67,24 +64,24 @@ OPENSIM=[AV]sitA.oss\
 all: $(SLZIP) $(OSZIP)
 
 clean:
-	$(RM) $(SLZIP) $(OSZIP) $(OPTIMIZED) $(OPENSIM)
+	$(PYTHON) build-aux.py rm $(SLZIP) $(OSZIP) $(OPTIMIZED) $(OPENSIM)
 
 optimized: $(OPTIMIZED)
 
 opensim: $(OPENSIM)
 
 $(SLZIP): $(OPTIMIZED) $(UNOPTIMIZED)
-	$(RM) $@
+	$(PYTHON) build-aux.py rm $@
 	zip $@ $(OPTIMIZED) $(UNOPTIMIZED)
 
 %.lslo: %.lsl
 	$(PYTHON) $(OPTIMIZER) -H -O addstrings,shrinknames,-extendedglobalexpr -p $(PREPROC_KIND) --precmd=$(PREPROC_PATH) $< -o $@
 
 $(OSZIP): $(OPENSIM)
-	$(RM) $@
+	$(PYTHON) build-aux.py rm $@
 	zip $@ $(OPENSIM)
 
 %.oss: %.lsl
-	$(PYTHON) prepare-for-oss.py $< > $@
+	$(PYTHON) build-aux.py oss-process $< > $@
 
 .PHONY : all clean optimized
diff --git a/AVsitter2/build-aux.py b/AVsitter2/build-aux.py
index 1fa509b..3db0314 100644
--- a/AVsitter2/build-aux.py
+++ b/AVsitter2/build-aux.py
@@ -1,35 +1,87 @@
 #!/usr/bin/env python
 # coding: utf8
 
-import sys, re
+import sys
 
 def prterr(s):
     sys.stderr.write(s + "\n")
 
-def main(argc, argv):
-    if argc < 2:
-        prterr(u'Need exactly 1 argument (input filename)')
-        return 1
+def usage():
+    """Show usage help."""
+    prterr(u"""Usage:
+python build-aux.py <command> [<args>]
+
+Where command can be:
+
+    oss-process <file>:
+        Processes the given file for OpenSim and outputs the result to
+        standard output. If <file> is not given, read from standard input.
+    rm <file> [<file>...]
+        Deletes the given list of files.
+""")
+
+def rm(filelist):
+    """Delete the given list of files, ignoring 'file not found' errors."""
+    import os
+    for i in filelist:
+        try:
+            os.unlink(i)
+        except OSError as e:
+            if e.errno != 2:
+                raise
+    return 0
+
+def oss_process(filename):
+    """Process a file for OpenSim Scripting."""
+    import re
 
     # Regex that replaces a line with its OSS version when one's specified.
     os_re = re.compile(r'^( *)(.*?)// ?OSS::(.*)$', re.MULTILINE)
 
-    f = open(argv[1], "r");
-    s = f.read()
-    f.close()
+    if filename is not None:
+        f = open(filename, "r");
+    else:
+        f = sys.stdin
+    try:
+        s = f.read()
+    finally:
+        if filename is not None:
+            f.close()
+
     # The U+FFFD character that AVsitter uses causes problems in OpenSim.
     # Replace it with U+001F (Unit Separator) which works fine.
     s = s.replace(b'\xEF\xBF\xBD', b'\x1F')
 
     # UUIDs in OpenSim
-    s = s.replace('f2e0ed5e-6592-4199-901d-a659c324ca94', '206fcbe2-47b3-41e8-98e6-8909595b8605')
-    s = s.replace('b30c9262-9abf-4cd1-9476-adcf5723c029', 'b88526b7-3966-43fd-ae76-1e39881c86aa')
+    s = s.replace('f2e0ed5e-6592-4199-901d-a659c324ca94',
+                  '206fcbe2-47b3-41e8-98e6-8909595b8605')
+    s = s.replace('b30c9262-9abf-4cd1-9476-adcf5723c029',
+                  'b88526b7-3966-43fd-ae76-1e39881c86aa')
     # TODO: Replace LockGuard texture UUIDs
 
     s = os_re.sub(r'\1\3', s)
     sys.stdout.write(s)
     return 0
 
+def main(argc, argv):
+    if argc < 2:
+        usage()
+        return 0
+
+    cmd = argv[1]
+    if cmd == 'rm':
+        return rm(argv[2:])
+
+    if cmd == 'oss-process':
+        if argc > 3:
+            usage()
+            return 1
+        filename = argv[2] if argc == 3 else None
+        return oss_process(filename)
+
+    usage()
+    return 1
+
 ret = main(len(sys.argv), sys.argv)
 if ret is not None and ret > 0:
     sys.exit(ret)