通过管道从 deb 包中提取目录

不幸的是， ar程序无法做到这一点。在网上翻遍了，没有找到合适的。尽管存档格式非常原始。所以我在perl中画了一个实现：

#!/usr/bin/env perl

# arpipe - extract to stdout file data.tar.xz from ar passed to stdin

use autodie;
open my $fh, '<-:raw';
my $member = shift;

# read from $fh count bytes
sub read_from {
  my $count = shift;
  my $bytes_read = read $fh, my $bytes, $count;
  die "got $bytes_read but expected $count" unless $bytes_read == $count;
  return $bytes;
}

# parse member header
sub parse_header {
  my $header = shift;
  my ($name, $timestamp, $oid, $gid, $filemode, $size, $ending) =
    unpack 'A16 A12 A6 A6 A8 A10 a2', $header;
  die "expected end of header" unless $ending eq "\x60\x0a";
  return ($name, $size);
}

# read and check archive header
my $header0 = read_from(8);
die "expected header" unless $header0 eq "!<arch>\x0a";

# loop through members of archive
while(1) {
  my $header = read_from(60);
  ($name, $size) = parse_header($header);
  last if $name eq $member;
  read_from($size);
}

print read_from($size);

限制：

• 描述说对齐到偶数字节边界，但我没有看到这样的档案，因此没有处理。

使用这样的东西：

$ cat файл.deb | ./arpipe data.tar.xz | tar -tJ