确定Shell程序中的相对路径还是绝对路径

问题描述：

如标题所述，我需要确定路径是相对路径还是绝对路径，何时运行程序:

As stated in the title, I need to determine when a program is ran if the path is relative or absolute:

./program #relative
dir/dir2/program #relative
~User/dir/dir2/program #absolute
/home/User/dir/dir2/program #absolute

这是我的测试用例.我到底该如何在Shell程序中执行此操作?

This are my test cases. How exactly could I go about doing this in a shell program?

或更笼统地说，如何检查这种情况下的路径$0是相对的还是绝对的?

Or more generally, how to check if a path, $0 in this case, is relative or absolute?

答

if [[ "$0" = /* ]]
then
   : # Absolute path
else
   : # Relative path
fi