python equivalent to perl's inplace edit mechanism

[David]

> #!/usr/bin/env perl
> #chgit script
> $^I = '';
> while(<>) {
>   s/mike/dave/g;
>   print;
> }
>

#!/usr/bin/python
import sys
lines = open(sys.argv[1]).readlines()
open(sys.argv[1], 'w').writelines([line.replace('mike', 'dave') for
line in lines])