Add string-replace.py (TriBITSPub#429)

Will help in future refactorings.  I mostly just added this as a precursor to
token-replace.py.

refactoring/string-replace.py

@@ -0,0 +1,64 @@
+#!/bin/env python3
+
+usageHelp = r"""
+
+Replace a given string with another string in a file (but only touch the file
+if there were changes).
+
+"""
+
+
+def getCmndLineOptions():
+  from argparse import ArgumentParser, RawDescriptionHelpFormatter
+
+  clp = ArgumentParser(description=usageHelp,
+    formatter_class=RawDescriptionHelpFormatter)
+
+  clp.add_argument(
+    "-s", dest="stringToReplace", required=True,
+    help="String to repalce" )
+
+  clp.add_argument(
+    "-r", dest="replacementString", required=True,
+    help="Replacement string" )
+
+  clp.add_argument(
+    "-f", dest="inputFile", required=True,
+    help="Input file (and also output if -o <file> not specified)" )
+
+  clp.add_argument(
+    "-o", dest="outputFile", default="",
+    help="Input file (and also output if -o <file> not specified)" )
+
+  options = clp.parse_args(sys.argv[1:])
+
+  if options.outputFile == "":
+    options.outputFile = options.inputFile
+
+  return options
+
+
+#
+#  Main()
+#
+
+if __name__ == '__main__':
+
+  import sys
+
+  inOptions = getCmndLineOptions()
+
+  with open(inOptions.inputFile, 'r') as file:
+    lines = file.readlines()
+
+  fileWasChanged = False
+  newLines = []
+  for line in lines:
+    newLine = line.replace(inOptions.stringToReplace, inOptions.replacementString)
+    if newLine != line:
+      fileWasChanged = True
+    newLines.append(newLine)
+
+  if (fileWasChanged or inOptions.outputFile != inOptions.inputFile):
+    with open(inOptions.outputFile, 'w') as file:
+      file.writelines(newLines)