如何在 Perl 中读取二进制文件 [英] How to read binary file in Perl

问题描述

我在编写 Perl 脚本以读取二进制文件时遇到问题.

I'm having an issue with writing a Perl script to read a binary file.

我的代码如下，其中 $file 是二进制格式的文件.我试图通过网络搜索和我的代码，试图把它打印出来申请，但似乎不能很好地工作.

My code is as the following whereby the $file are files in binary format. I tried to search through the web and apply in my code, tried to print it out, but it seems it doesn't work well.

目前它只打印&&&&&&&&&"和"ppppppppppp"，但我真正想要的是它可以打印出每个$line，以便我稍后可以进行其他一些后期处理.另外，我不太确定 $data 是什么，因为我看到它是文章示例中代码的一部分，说明假设是一个标量.我需要有人可以指出我的代码中哪里出错了.以下是我所做的.

Currently it only prints the '&&&&&&&&&&&" and ""ppppppppppp", but what I really want is it can print out each of the $line, so that I can do some other post processing later. Also, I'm not quite sure what the $data is as I see it is part of the code from sample in article, stating suppose to be a scalar. I need somebody who can pin point me where the error goes wrong in my code. Below is what I did.

my $tmp = "$basedir/$key";
opendir (TEMP1, "$tmp");
my @dirs = readdir(TEMP1);
closedir(TEMP1);

foreach my $dirs (@dirs) {
    next if ($dirs eq "." || $dirs eq "..");
    print "---->$dirs\n";
    my $d = "$basedir/$key/$dirs";
    if (-d "$d") {
        opendir (TEMP2, $d) || die $!;
        my @files = readdir (TEMP2); # This should read binary files
        closedir (TEMP2);

        #my $buffer = "";
        #opendir (FILE, $d) || die $!;
        #binmode (FILE);
        #my @files =  readdir (FILE, $buffer, 169108570);
        #closedir (FILE);

        foreach my $file (@files) {
            next if ($file eq "." || $file eq "..");
            my $f = "$d/$file";
            print "==>$file\n";
            open FILE, $file || die $!;
            binmode FILE;
            foreach ($line = read (FILE, $data, 169108570)) {
                print "&&&&&&&&&&&$line\n";
                print "ppppppppppp$data\n";
            }
            close FILE;
        }
    }
}

我已经修改了我的代码，如下所示.现在我可以读取 $data.感谢 J-16 SDiZ 指出这一点.我试图将我从二进制文件中获得的信息推送到一个名为@array"的数组中，想从数组中 grep 数据以获取匹配p04"但失败的字符串.有人能指出错误在哪里吗?

I have altered my code so that it goes like as below. Now I can read the $data. Thanks J-16 SDiZ for pointing out that. I'm trying to push the info I got from the binary file to an array called "@array", thinkking to grep data from the array for string whichever match "p04" but fail. Can someone point out where is the error?

my $tmp = "$basedir/$key";
opendir (TEMP1, "$tmp");
my @dirs = readdir (TEMP1);
closedir (TEMP1);

foreach my $dirs (@dirs) {
    next if ($dirs eq "." || $dirs eq "..");
    print "---->$dirs\n";
    my $d = "$basedir/$key/$dirs";
    if (-d "$d") {
        opendir (TEMP2, $d) || die $!;
        my @files = readdir (TEMP2); #This should read binary files
        closedir (TEMP2);

        foreach my $file (@files) {
            next if ($file eq "." || $file eq "..");
            my $f = "$d/$file";
            print "==>$file\n";
            open FILE, $file || die $!;
            binmode FILE;
            foreach ($line = read (FILE, $data, 169108570)) {
                print "&&&&&&&&&&&$line\n";
                print "ppppppppppp$data\n";
                push @array, $data;
            }
            close FILE;
        }
    }
}

foreach $item (@array) {
    #print "==>$item<==\n"; # It prints out content of binary file without the ==> and <== if I uncomment this.. weird!
    if ($item =~ /p04(.*)/) {
        print "=>$item<===============\n"; # It prints "=><===============" according to the number of binary file I have.  This is wrong that I aspect it to print the content of each binary file instead :(
        next if ($item !~ /^w+/);
        open (LOG, ">log") or die $!;
        #print LOG $item;
        close LOG;
    }
}

再次，我更改了我的代码如下，但它仍然不起作用，因为它无法通过检查日志"文件来正确地grepp04".它确实grep了整个文件，包括这样的二进制文件@^@^@^@^G^D^@^@^@^^@p04bbhi06^@^^@^@^@^@^@^@^@^@hh^R^@^@^@^^@^@^@p04lohhj09^@^@^@^^@@".我所指的是它只对 p04 进行 grep 任何操作，例如 grepping p04bbhi06 和 p04lohhj09.这是我的代码的运行方式:-

Again, I changed my code as following, but it still doesn't work as it do not able to grep the "p04" correctly by checking on the "log" file. It did grep the whole file including binary like this "@^@^@^@^G^D^@^@^@^^@p04bbhi06^@^^@^@^@^@^@^@^@^@hh^R^@^@^@^^@^@^@p04lohhj09^@^@^@^^@@" . What I'm aspecting is it do grep the anything with p04 only such as grepping p04bbhi06 and p04lohhj09. Here is how my code goes:-

foreach my $file (@files) {
    next if ($file eq "." || $file eq "..");
    my $f = "$d/$file";
    print "==>$file\n";
    open FILE, $f || die $!;
    binmode FILE;
    my @lines = <FILE>;
    close FILE;
    foreach $cell (@lines) {
        if ($cell =~ /b12/) {
            push @array, $cell;
        }
    }
}

#my @matches = grep /p04/, @lines;
#foreach $item (@matches) {
foreach $item (@array) {
    #print "-->$item<--";
    open (LOG, ">log") or die $!;
    print LOG $item;
    close LOG;
}

推荐答案

使用:

$line = read (FILE, $data, 169108570);

数据在$data中；$line 是读取的字节数.

The data is in $data; and $line is the number of bytes read.

       my $f = "$d/$file" ;
       print "==>$file\n" ;
       open FILE, $file || die $! ;

我猜完整路径在 $f 中，但您正在打开 $file.(在我的测试中——即使 $f 也不是完整路径，但我猜你可能还有其他一些胶水代码......)

I guess the full path is in $f, but you are opening $file. (In my testing -- even $f is not the full path, but I guess you may have some other glue code...)

如果您只想遍历目录中的所有文件，请尝试 File::DirWalk 或 File::Find.

If you just want to walk all the files in a directory, try File::DirWalk or File::Find.

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