To extract the contents of a .deb file without opening it on Debian or Ubuntu Linux, you can use the dpkg command with the -x option. The syntax is as follows:
dpkg -x package.deb destination
Replace package.deb with the name of the .deb file, and destination with the directory where you want to extract the contents of the file.
For example, to extract the contents of a file called mypackage.deb to the /tmp directory, you would run the following command:
dpkg -x mypackage.deb /tmp
This will extract all of the files contained in the .deb file to the /tmp directory.
If you want to extract only a specific file from the .deb file, you can use the -X option followed by the path of the file you want to extract. The syntax is as follows:
dpkg -X package.deb path/to/file destination
For example, to extract a file called README.txt from the mypackage.deb file to the current directory, you would run the following command:
dpkg -X mypackage.deb usr/share/doc/mypackage/README.txt .
This will extract the README.txt file from the mypackage.deb file to the current directory.
Keep in mind that the dpkg command is used to manage packages on Debian and Ubuntu systems, and it is not intended for extracting individual files from .deb files. If you just want to extract the contents of a .deb file, you can use a tool like ar or bsdtar.