Perl diff two files

The provided subroutine is called for all unique files, and for every pair of 'different' files encountered, with the following signature:. For 'unique' files i. The following optional arguments are supported, passed in using a hash reference after the three required arguments to compare e. Does Perl have a inbuilt diff or do I need to use the unix diff utility? I don't want to implement my own diff algorithm for this. I do need the information as to where my files differ, but I do not need to use the unix diff utility necessarily.

That was just an example. You could try using Text::Diff. If I only needed to know that they were the same i. There's a vanishingly small chance that two different files could have the same MD5 digest, so you might even try Digest::SHA1.

If you want to find out which lines are different, then you can use Algorithm::Diff , perhaps in conjunction with Tie::File. However, there is also a diff program that comes with Algorithm::Diff if you don't have a diff tool on your target platform. Although you can shell out to that, you might just want to copy what it does into a subroutine.

Text::Diff is built on top of Algorithm::Diff , so it might already do want you want. No, Perl doesn't have an inbuilt "diff" facility. Either you use an external module, or use Perl's data structures hashes, arrays etc or you create filehandles for both files, and iterate the files using the filehandle while loops , comparing them line by line. This method assumes your files are sorted. Another not so elegant way is to call "diff" from Perl, but I advise against that.

Lastly, if Perl is not a must, just use the Unix diff utility write a shell script. Documentation is here. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

This is a bit trickier than it first seems. You can put the values of File 1 into a hash, and then print out the values in File 2 if they're not in File 1. This will give you a list of unique values in File 2, but not unique values in File 1. Therefore, you need to create two hashes, one for FIle 1 and one for File 2, and then go through each and compare them against each other:. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 8 years, 6 months ago. Active 8 years, 6 months ago. Viewed 10k times. File1: File2: Expected Output: This is what I've got so far, which isn't working:! Improve this question.

Yoboy Yoboy 15 1 1 gold badge 1 1 silver badge 3 3 bronze badges. Very early in my second and current career, I wrote some code very much like this. That's before I discovered diff. Take a look at man diff. Add a comment. Active Oldest Votes. Otherwise, see below: Here's one algorithm to do the comparison. Can it be done using SED? Hi Masters, I have two files named file1 and file2. Both the files contains the same contents with some difference in comments,space.

But no content change. I tried to find the diff between the two files to make sure that contents are same. For that i tried diff -ibw file1 file2 But Hi, i am new to perl scripting.. Find duplicates from multuple files with 2 diff types of files.

I need to compare 2 diff type of files and find out the duplicate after comparing each types of files: Type 1 file name is like: file1. The other file is file1. Thanks Gusla 1 Reply. Hello, I want to compare two files.