用tar命令解压.tar包的时候会出现以下错误：
gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error exit delayed from previous errors
You used "tar -zxvf" for the second command. the 'z' option tells tar to use gzip to uncompress the file. Since you already uncompressed it in the first command, gzip doesn't know what to do with it, and it consequently croaks. Tar stops because gzip encountered a problem. So, with the file you have now, you would extract it with:
tar -xvf xxxxxx.x.x.tar
I would go back and re-gzip the tar file though (to save space):
gzip xxxxxx.x.x.tar
tar -zxvf xxxxxx.x.x.tar.gz
只需要把命令令改为：
tar -xvf xxxx.tar.gz