--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/lsex.py	Thu Oct 15 11:41:26 2009 -0400
@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+import os
+
+# make sure duplicate path elements aren't printed twice
+def ordered_set(alist):
+    seen = set()
+    new = []
+    for item in alist:
+        if item in seen:
+            continue
+        seen.add(item)
+        new.append(item)
+    return new
+
+def lsex(path=None):
+    """
+    list executable files on the path
+    o path: list of directories to search.  if not specified, use system path
+    """
+
+    if path is None:
+        # use system path
+        path = ordered_set(os.environ['PATH'].split(':'))
+
+    executables = []
+
+    # add the executable files to the list
+    for i in path:
+        if not os.path.isdir(i):
+            continue
+        files = [ os.path.join(i,j) for j in os.listdir(i) ]
+        files = filter(lambda x: os.access(x, os.X_OK), files)
+        files.sort() # just to make the output pretty
+        executables.extend(files)
+    return executables
+
+if __name__ == '__main__':
+    for i in lsex():
+        print i