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 .

Answer 2

The is also another useful way, like "readlink -m $filename"

First of all, it works without requirement for target file to exist. Secondly, it will handle symlinks and get really real path.

Answer 3

// For C++ with Gnome Gtkmm3 libraries
#include <glibmm.h>
#include <giomm.h>

  string PathRel2Abs(string relpath) {
  Glib::RefPtr<Gio::File> file = Gio::File::create_for_path(relpath);
  return file->get_path();
}

Answer 4

As Paul mentioned, use realpath(). Please note though, that since many file systems in Linux support hard links, any given directory can have a number of different absolute paths.

Answer 5

Check out the realpath function.

#include <stdlib.h> 
#include <stdio.h> 
#include <linux/limits.h>
int main() 
{ 
        char resolved_path[PATH_MAX]; 
        realpath("../../", resolved_path); 
        printf("\n%s\n",resolved_path); 
        return 0; 
} 

Answer 6

Try realpath:

$ man realpath

This is also available in BSD, OS X, et al.