如何尾部位于压缩的 tar 文件中的文件的最后 n 行

Question

Ubuntu 16.04
Bash 4.4.20

I am wanting to tail the last 30 lines of a SQL file located in a tar.gz file. I noticed that the SQL backups were failing due to a locked file. Instead of me untarring the entire compressed file, I'd like to simply tail the SQL backup and then grep for certain phrases.

This StackOverflown Thread explains that this is not possible with zipped files. Does this also apply to tar files that are created like so:

tar czf name.tar.gz foldername  

If this has been explained in another thread, please delete this thread and I'll keep searching.

Answer 1

You can use tar's -O option to print content of file then using | (pipe) | (pipe) , you can apply basic unix operations, like tail:

tar zxvf name.tar.gz <file_to_read> -O | tail

Sample command, to read last two lines of a file A1.txt

tar zxvf B.tar.gz B/A1.txt -O | tail -2

Here B is a directory on which I have ran tar command, it contains many files along with file A1.txt