How to handle .tar.md5 files

Question

I was wondering about how to create / extract / verify .tar.md5 files. These files are used when flashing images to android devices, see here for example.

As far as I can tell the checksum is appended to the file like this:

cp file.tar file.tar.md5
md5sum file.tar >> file.tar.md5

Firstly I would like to know how to extract the file. Can I simply use tar -xf on the file.tar.md5?

How can I verify the integrity of the file? I would like to remove the last bytes (containing the checksum) from the file to obtain the original file back. I guess you would have to use a regexp to match the checksum file.tar? Is something like this implemented somewhere already?

Answer 1

First of all tar -xf should work since tar continues while it matches its' packing algorithm. If the file stops matching so would tar. Also most archive managers such as 7-zip or winrar will open it if you remove the ".md5". They might print error regarding mismatch with the end of the file, ignore it.

As for verifying the file:

• print out the stored md5sum: tail -z -n 1 [File name here].tar.md5

• calculate the md5sum of the tar part of the file: head -z -n -1 [File name here].tar.md5 | md5sum

Answer 2

What works for me with Ubuntu 19.10 is:

• download single-file 4 GiB zip from sammobile com
• unzip to several *.tar.md5
• run the below command-line

.

for F in *.tar.md5; do echo -n "$F " &&
  EXP=($(tail --lines=1 "$F")) &&
  ACT=($(head --lines=-1 "$F" | md5sum)) &&
  if [ ${EXP[0]} = ${ACT[0]} ]; then echo -n "md5ok " &&
  tar --extract --file "$F" && echo "done" 
  else echo "FAIL"; fi; done &&
unlz4 --multiple --verbose *.lz4
AP_G965U1UEU3ARL1_CL14745140_QB21029084_REV01_user_low_ship_MULTI_CERT_meta.tar.md5 md5ok done
BL_G965U1UEU3ARL1_CL14745140_QB21029084_REV01_user_low_ship_MULTI_CERT.tar.md5 md5ok done
CP_G965U1UEU3ARL1_CP11407818_CL14745140_QB21029084_REV01_user_low_ship_MULTI_CERT.tar.md5 md5ok done
CSC_OMC_OYM_G965U1OYM3ARL1_CL14745140_QB21029084_REV01_user_low_ship_MULTI_CERT.tar.md5 md5ok done
HOME_CSC_OMC_OYM_G965U1OYM3ARL1_CL14745140_QB21029084_REV01_user_low_ship_MULTI_CERT.tar.md5 md5ok done
…

But we should all try to get away from bash