Extract .tar.gz inside a .tar file

Question

I have a double-compressed file (.tar.gz inside a .tar) and i would like to know if there is any way to automatically extract it from a bash script. I tried two approaches:

tar -xf $1 #the first .tar file is passed as argument to the bash script
tar -xf /home/user/working_dir/file_inside.tar.gz #passing the absolute path to the file assuming the .tar file was extracted as expected.

tar -xf $1 | tar -xf `xargs` 

But i get the error: tar: /file_inside.tar.gz: Cannot open: No such file or directory.

Thanks in advance.

Answer 1

If you know relative filename of intermediate file, try

tar -xf $1 -O path/to/file.tar.gz | tar xf - 

where

   -O, --to-stdout
          Extract files to standard output.

1. you might need -z flag in second tar

2. please note that - is synonym for stdin, maybe that what you meant (tar -xf $1 | tar -xf xargs (*) ) ?

   tar -xf $1 | tar -xf - 
   

(*) xargs is backquoted

---

If you feel adventurous, you can also try option --to-command=COMMAND

tar -xf $1 --to-command="tar -xzf -" path/to/file

1. I advise to test before going "production"
2. Do not use absolute path