How to get the absolute path for a given relative path programmatically in Linux?

Question

How to get the absolute path for a given relative path programmatically in Linux?

Incase of Windows we have the _fullpath() API. In other words, I mean

Answer 1

Running on RedHat 5.3, realpath doesn't exist but readlink is installed. You can use it on relative paths and symlinks, plus it will resolve symlinks recursively for you. It's thus a better option that realpath in my opinion

readlink -f .