I created a hard link
$ ln hours.sh hours_link
test it
$ ls -l hours*
-rw-r--r-- 2 me staff 653 Apr 12 2018 hours.sh
-rw-r--r-- 2 me staff 653 Apr 12 2018 hours_link
remove it with unlink
$ unlink hours_link
$ ls -l hours*
-rw-r--r-- 1 me staff 653 Apr 12 2018 hours.sh
so far so good, but unlink
can delete the original file which is not a link
$ cp hours.sh hours.bak.sh
$ unlink hours.sh
$ ls | grep hours.sh
#not return anything, hours.sh is deleted
check the manual and very surprised
unlink - call the unlink function to remove the specified file
rm - remove files or directories
If not just take it for granted, how should I understand this conversion?