UNIX for Dummies Questions & Answers

Hi

1) I have .tar file which i am going to extract in a particular environment.
Now the files after extracting might be changed over time and I want to take the new tar of these files to put the same files into another env.
The existing tar contains tar contains more than 100 files, so is it possible that I take new tar using previous .tar file or creating a new tar with listing all files is the only way.

2) While extracting the tar using xvf option, if there is a file that already exists would it be overwritten(This is required)

Thanks

Have you looked at the tar man page on your system?

It would seem that tar r or tar u could be used to add updated files to your archive or update files in your archive, respective, depending on what type of file is holding your current tar archive.

Do you have some reason to think that tar x doesn't do what you want?

Sounds like homework, which would need to be posted in: https://www.unix.com/homework-and-coursework-questions/
Please follow the homework posting guidelines that are sticky there.

Hi Cragun

I have used the tar -u but it is adding the file if u specify to the tar file.
It is not updating the whole list of files in the tar.

With both tar -u and -r, I have to specify the file name that needs to be changed. But i want the whole list of files in the .tar to be updated.

Thanks
Rajnish

OK. Now I get it. You want tar to read your mind and magically devine what files in your archive you want to update.

Sorry, but tar doesn't work that way. The way it works is you tell tar:It sounds like you just want to use tar c to recreate your archive from your original list of files. So, just use the command that created your archive in the first place to recreate your archive after you have updated the files you want in your updated archive.

You could also consider using tar t to get a list of files in an archive and use cpio or pax or tar c to update that list of files into another archive.

Create a new tar file, and give the directory so it will find all files in it.
Have the tar files in another directory so there is no tar within a tar.

I suggest reading the man page of tar because all you need is there in plain sight.

Use "t" to list the names of the files in the tar archive, then feed this list to another call of tar as arguments to "u". See the details of both subcommands at the man page. Try out both commands on a test file to see the effects.

I hope this helps.

bakunin