Tar: Extract only files (not sub-directories)

Question

How do I extract only files from a directory in a tar archive? I need to extract all the files in the directory, not specific files. For example, with a tar archive of this structure:

wordpress
 --wp-admin
 --wp-content
 --wp-includes
 --index.php
 --license.txt
 --readme.html

I want to extract only the 3 (or more) files in the wordpress directory not the sub-directories.

Note that the other solutions I could find on this site are about extracting specific files. My question is about extracting all files.

Answer 1

Unless I can make an assumption about the format of directory names and file names, I can't find any way of extracting files at a particular level without also extracting (empty) directories at that same level. (If file names contain a dot but directories do not, then another answer will be sufficient.)

Consider 370358.tar with this content

wordpress/
wordpress/index.php
wordpress/license.txt
wordpress/readme.html
wordpress/wp-admin/
wordpress/wp-admin/admin.php
wordpress/wp-content/
wordpress/wp-content/2021/
wordpress/wp-content/2021/01/
wordpress/wp-content/2021/01/19/
wordpress/wp-content/2021/01/19/today.txt
wordpress/wp-content/content.txt
wordpress/wp-content/here.txt
wordpress/wp-content/some.txt
wordpress/wp-includes/

You can extract files matching wordpress/* like this

tar xf /tmp/370358.tar --wildcards --exclude '*/*/*' && rmdir */* 2>/dev/null

ls -R wordpress
wordpress:
index.php  license.txt  readme.html

Notice the trailing rmdir. We cannot tell tar to skip directory creation even though the resulting directories will be empty, so we simply delete them afterwards.

If you don't actually want the wordpress directory to be included in the extraction,

tar xf /tmp/370358.tar --strip-components 1 --wildcards --exclude '*/*/*' && rmdir * 2>/dev/null

ls -R
.:
index.php  license.txt  readme.html

Answer 2

Assuming GNU tar, you could extract the archive through a short bash script:

tar -x -f archive.tar --to-command=./script.sh

... where script.sh is the executable script

#!/bin/bash

if [ "$TAR_FILETYPE" = f ] &&
   [[ $TAR_FILENAME == wordpress/* ]] &&
   [[ $TAR_FILENAME != wordpress/*/* ]]
then
    mkdir -p "${TAR_FILENAME%/*}" &&
    cat >"$TAR_FILENAME" &&
    chmod "$TAR_MODE" "$TAR_FILENAME" &&
    chown "$TAR_UNAME:$TAR_GNAME" "$TAR_FILENAME" || true
else
    cat >/dev/null
fi

The TAR_* variables used here are set in the script's environment by GNU tar, and the data of the file currently being extracted is arriving over standard input.

The tests used in the script is to make sure that

1. The file we're extracting is a regular file, and
2. The file is located in the wordpress directory and nowhere else.

To extract a file, we simply make sure that the file's directory exists, redirect the standard input to the correct filename, and then modify the file mode and ownerships so that the permissions and owners are correct.

You could obviously also give the script in-line on the tar command line:

tar -x -f archive.tar --to-command='bash -c "
    if [ \"\$TAR_FILETYPE\" = f ] &&
       [[ \$TAR_FILENAME == wordpress/* ]] &&
       [[ \$TAR_FILENAME != wordpress/*/* ]]
    then
        mkdir -p \"\${TAR_FILENAME%/*}\" &&
        cat >\"\$TAR_FILENAME\" &&
        chmod \"\$TAR_MODE\" \"\$TAR_FILENAME\" &&
        chown \"\$TAR_UNAME:\$TAR_GNAME\" \"\$TAR_FILENAME\" || true
    else
        cat >/dev/null
    fi"'

Answer 3

This will extract all the files in a directory in a tar file, without going into the sub-directories:

tar --wildcards --no-wildcards-match-slash -xvf file.tar.gz directory_in_tar/*.*