Extract file from directory inside tar file without creating that directory

Question

I have a tarfile which has the following structure:

- dir1
 -- file
- dir2
- dir3

If I try running tar -xf tarfile.tar.gz dir1/file, dir1 containing the file will be created. I would like instead to just get the file without the directory in between. I could move the file and delete the directory, but I was wondering if the tar command offers support for doing that directly.

I am using Alpine Linux.

Answer 1

POSIXly (except for the gunzip part that is not a POSIX command):

gunzip < file.tar.gz | pax -rs'|.*/||' dir1/file1

With bsdtar:

tar -s'|.*/||' -xf file.tar.gz dir1/file1

With GNU tar:

tar --transform='s|.*/||' -xf file.tar.gz dir1/file1

With star:

star -s '|*/||' -x -f file.tar.gz dir1/file1

Note that for some of those, if the file is a a symlink, the substitution will also affect the target of the symlink.

Answer 2

You could extract to stdout (-O) and pipe it to the wanted filename.

Answer 3

Here is my solution in Ruby. I make no attempt to handle sym-links properly, but that could be added of course.

outfiles = `tar zxvf #{ARGV[0]}`
root_dirs = {}
outfiles.each_line do |l|
  s = l.split('/')
  root_dirs[s[0]] = 1
  `mv #{l.chomp} ./#{s[-1]}`
end
root_dirs.each_key {|rd| `rm -rf #{rd}`}