Thread: Comparing Files.

  1. #1
    Registered User
    Join Date
    Aug 2004

    Comparing Files.

    Hey guys,

    I have 30 files full of mac addresses. What do you think would be the best way to compare all these files and output the mac addresses that show up in all 30 files to a new file. Is there a compare function? Should I read them into arrays and compare them? Any ideas would help out, I am a newbie to C but understand the basics. Thanks

  2. #2
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
    The edge of the known universe
    Or is this a slightly different problem?

    If the files are text files, one MAC address per line, then I can do this using a 2-line AWK program
    { count[$1]++ }
    END { for ( i in count ) if ( count[i] == 30 ) print i
    Save that as a file called program.

    Then do
    awk -f program mac_file*.txt
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
    Registered User
    Join Date
    Aug 2004
    Yes it is the same question, I forgot I asked here already. Thanks for your reply. I like your way of doing it.

  4. #4
    Registered User Draco's Avatar
    Join Date
    Apr 2002
    I would suggest separating each MAC address by strings, and using the function strcmp() to compare. If you dont know how to do this specifically, the FAQ should have all the info you need. If it doesn't, post again and I will do what I can

    Ahhh! Curses!

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