diff --git a/files/string_replace.py b/files/string_replace.py
new file mode 100644
index 0000000..a94d3d0
--- /dev/null
+++ b/files/string_replace.py
@@ -0,0 +1,20 @@
+#Change one string into another throughout a file
+#!/usr/bin/env python
+import os, sys
+nargs = len(sys.argv)
+if not 3 <= nargs <= 5:
+    print "usage: %s search_text replace_text [infile [outfile]]" % \
+        os.path.basename(sys.argv[0])
+else:
+    stext = sys.argv[1]
+    rtext = sys.argv[2]
+    input_file = sys.stdin
+    output_file = sys.stdout
+    if nargs > 3:
+        input_file = open(sys.argv[3])
+    if nargs > 4:
+        output_file = open(sys.argv[4], 'w')
+    for s in input_file:
+        output_file.write(s.replace(stext, rtext))
+    output.close( )
+    input.close( )
\ No newline at end of file