报错信息如下：
# tar -zxvf extmail-1.2.tar.gz
tar: This does not look like a tar archive
tar: Skipping to next header
tar: Exiting with failure status due to previous errors
解决：
# file extmail-1.2.tar.gz
extmail-1.2.tar.gz: gzip compressed data, from Unix
# gzip -d extmail-1.2.tar.gz
# tar -xf extmail-1.2.tar
tar: This does not look like a tar archive
原文：http://guowang327.blog.51cto.com/6513732/1732078