Want Perl equivalent of linux strings command to extract strings from binary file

Discussion in 'Programming/Scripts' started by rjamesd, Nov 25, 2009.

  1. rjamesd

    rjamesd New Member

    Hi,
    I'm looking for a Perl function that does the same thing as the Linux strings command.

    The strings command will output a list of strings contained in any file, including a binary file that has strings embedded with in.

    Regular expressions don't seem to work very well (or at all) with searching for strings in binary files.

    I've searched here already but not found answers.

    I want a Perl equivalent as I want to make my Perl code platform independent. If I call strings from Perl then I have made my code dependent on the strings command being available from the underlying operating system.
     
  2. id10t

    id10t Member

    So include a copy of strings!

    Its already on *nix systems - including OS X - and there are win32 versions available precompiled.
     
  3. rjamesd

    rjamesd New Member

    Thanks - yes Windows strings is at:

    http://technet.microsoft.com/en-us/sysinternals/bb897439.aspx

    I downloaded unzipped and placed this in the same folder as the Perl script.

    It works straight out of the box (on Windows XP at least) but be aware that first time it is run it will ask for a license agreement, thereafter you wont be asked.

    Just for info, I can then regex match the string I am looking for from this - and extract it out using the following code

    Code:
    # get just printable character sequences from binary file called the string stored in $binaryFilename 
    my $fileStrings = `strings $binaryFilename`; # note backward single quote to capture output of executing command enclosed
    
    # $fileStrings is just the printable character sequences in the file (minimum 3 chars - see technet link above about how to change)
    
    # do the regex
    if ( $fileStrings =~ # a regex here # )
    {
    # if got here regex found match
    # so
    # get start and beginning of string using $` and $& Perl global system variables set to values from the last regex
    my $embeddedStringStart = length($`);
    my $embeddedStringLength = length($&);
    my $embeddedString = substr( $fileStrings, $embeddedStringStart, $embeddedStringLength );
    
    # go on to do something with the $embeddedString ...
    }
     
    Last edited: Nov 25, 2009
  4. id10t

    id10t Member

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