课后作业：

#!/bin/bash
#!/bin/bash

mkdir ~/dir
mkdir ~/dir/dir1
mkdir ~/dir/dir2
cp * ~/dir/dir1/
cp *.sh ~/dir/dir2/
tar -cJf ~/dir/dir2.tar.xz ~/dir/dir2
mv ~/dir/dir2.tar.xz ~/dir/dir1/
tar -xJf ~/dir/dir1/dir2.tar.xz -C ~/dir/dir1/
tree ~/dir

思维导图：