in reply to replacing password in a file

This is a very basic Perl question, concerning replacing one value in a file with another. You will find many such questions here - some even this week. That should be enough to get you started.

Your problem is only slightly complicated because you need to deal with encrypted passwords. You will need to find out what method is used (MD5? SHA? DES?), and locate the Perl module that will perform that function. Search CPAN here to find them. Perl has the crypt() function that uses DES, so you may not need a special module.

Dum Spiro Spero

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Re^2: replacing password in a file
by afoken (Chancellor) on May 13, 2015 at 18:57 UTC
    Perl has the crypt() function that uses DES

    Are you sure? All documentation I found just states that crypt() calls crypt() in the C library. And that function in the C library is free to choose any algorithm. Maybe crypt() in your perl on your computer uses DES. But that is just how the C library on your computer is implemented. On other computers, the C library may use a different algorithm, perhaps even choose one of a few depending on some external configuration.

    Alexander

    --
    Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)
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      My copy of "The Perl 5 Programmer's Reference" says it uses DES. It's from 1997. Next time I'll double check with perldoc.

      Dum Spiro Spero
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        My copy of "The Perl 5 Programmer's Reference"

        Has a review here: The Perl 5 Programmer's Reference. I think I saw it in a store or some illegal copy somewhere on the net, and it is barely more than the perldoc that came with perl.

        says it uses DES. It's from 1997. Next time I'll double check with perldoc.

        Just ran a search for "DES" on my local POD for perl 5.18.1 (from 2013), and got only one match: perlcygwin allows to compile perl with -lcrypt, explicitly mentioning DES: "The crypt package distributed with Cygwin is a Linux compatible 56-bit DES crypt port by Corinna Vinschen."

        Since the book is from 1997, and is essentially a printed perldoc, a Perl version from that time should mention DES.

        perl 5.004, dated 15 May 1997 (first from 1997 on CPAN)
        perlfunc says: "Encrypts a string exactly like the crypt(3) function in the C library", no trace of DES. Not even a brute force search is successful, only tons of false positives (DESTROY, DESCRIPTION).
        perl 5.003_07, dated 10 Oct 1996 (the oldest one on CPAN)
        perlfunc has the same text, and the search has again only false positives.

        So, where does the DES information come from?

        A really brute force search across all perl versions on perl5.git.perl.org has quite a few matches with many false positives and many test scripts, but none before 1997-12-24. Perl 5.003_07 has only false positives, i.e. no trace of DES in Perl 5.003_07. Older versions have been excluded by the git brute force search.

        The Win32/cygwin ports had DES for ages, using a third party DES crypt() implementation. But for other systems, DES is not mentioned (or at least I did not find any hints.)

        So the book must be either wrong (assuming crypt implements DES for all operating systems) or badly worded (making you think Win32 DES crypt or DES crypt in some libc apply to all operating systems).

        Alexander

        --
        Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)
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        user1 { pwd=hello group=accounts } user2 { pwd=godknows group=admin } i want to change the pasword of a particular user. I used grep function to get the pasword line no. after tht i m using awk command to change the pasword. But how can i used it I cant understand.plz help me ,how can i update tht pasword.
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