Today I had a large (re: 4GB) file that I needed to do some search and replace on, and none of my text editors including my beloved Textmate could even open the file. So I turned to the most trusty of tools in my tool chest which is python!

f = open(infile, "r")
n = open(outfile, "w")
for line in f:
    output = line.replace(oldtext, newtext)
    n.write(output)

In just a couple of minutes I had a new file with the changes I needed. Its pretty basic stuff, but non-programmers (especially those that don't use languages like python) might not think of trying.