tar - List of extracted files

Question

How can I extract files from a .tar.gz archive while keeping a trace of the extracted files?

For example, let's say I have the following file structure...

ROOT
 ╠═▶ children
 ║    ╠═▶ joe.txt
 ║    ╚═▶ george.txt
 ╠═▶ bar.txt
 ╠═▶ foo.txt
 ╚═▶ A̲R̲C̲H̲I̲V̲E̲.t̲a̲r̲.b̲z̲
      ├─▷ children
      │    ├─▷ joe.txt
      │    └─▷ bob.txt
      ├─▷ hello.txt
      ├─▷ world.txt
      └─▷ foo.txt

Now, if I extract the files from the archive while keeping the newer files in place I'd like to know which ones have been extracted so I can do something like this:
tar xf ./ARCHIVE.tar.gz --keep-newer-files | xargs -I EXTRACTED_FILE echo EXTRACTED_FILE

Answer 1

I will use the option --to-command to trigger the print of all extracted files

the argument is a command that will use the env variable TAR_FILENAME to have the file name , and will receive thee file on STDIN

So you must read STDIN and create the extracted file , you can print on STDOUT the file you created

tar -xzf ../ARCH.tgz --keep-newer-files \
   --to-command="sh -c $(printf '%q' \
  'mkdir -p "$(dirname "$TAR_FILENAME")";dd of="$TAR_FILENAME" >/dev/null 2>&1;echo "#EXTRACTED#$TAR_FILENAME" ')" > output_tar.txt

and in output_tar.txt you will have a line for each extracted file .

See Writing to an External Program for more details

Answer 2

Depending of my requirement, I sometimes need to list all available extracted files matching the archive content (whether or not newer).

In that case, I can list the files effectively extracted, once the tar extraction was performed (or not).

I do it like this:

tar -xzf ./ARCH.tgz --keep-newer-files
for file in $(tar -tf ./ARCH.tgz 2>/dev/null)
do
  if [[ -e $file && ! -d $file ]]
  then
    echo $file
  fi
done > output_tar.txt

A maybe less explicit but concise solution using xargs is:

tar -tf ./ARCH.tar 2>/dev/null | xargs -L1 bash -c 'if [[ -e $0 && ! -d $0 ]]; then echo $0; fi;'