How should I compare two txt files separately coming from windows/dos and linux/unix

[higer]

On Jun 11, 1:08 pm, John Machin <sjmac... at lexicon.net> wrote:
> Chris Rebert <clp2 <at> rebertia.com> writes:
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> > On Wed, Jun 10, 2009 at 8:11 PM, higer<higerinbeijing <at> gmail.com> wrote:
> > > I just want to compare two files,one from windows and the other from
> > > unix. But I do not want to compare them through reading them line by
> > > line. Then I found there is a filecmp module which is used as file and
> > > directory comparisons. However,when I use two same files (one from
> > > unix,one from windows,the content of them is the same) to test its cmp
> > > function, filecmp.cmp told me false.
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> > > Later, I found that windows use '\n\r' as new line flag but unix use
> > > '\n', so filecmp.cmp think that they are different,then return false.
> > > So, can anyone tell me that is there any method like IgnoreNewline
> > > which can ignore the difference of new line flag in diffrent
> > > platforms? If not,I think filecmp may be not a good file comparison
>
> > Nope, there's no such flag. You could run the files through either
> > `dos2unix` or `unix2dos` beforehand though, which would solve the
> > problem.
> > Or you could write the trivial line comparison code yourself and just
> > make sure to open the files in Universal Newline mode (add 'U' to the
> > `mode` argument to `open()`).
> > You could also file a bug (a patch to add newline insensitivity would
> > probably be welcome).
>
> Or popen diff ...
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> A /very/ /small/ part of the diff --help output:
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>   -E  --ignore-tab-expansion  Ignore changes due to tab expansion.
>   -b  --ignore-space-change  Ignore changes in the amount of white space.
>   -w  --ignore-all-space  Ignore all white space.
>   -B  --ignore-blank-lines  Ignore changes whose lines are all blank.
>   -I RE  --ignore-matching-lines=RE  Ignore changes whose lines all match RE.
>   --strip-trailing-cr  Strip trailing carriage return on input.
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> Cheers,
> John

Tool can certainly be used to compare two files,but I just want to
compare them using Python code.