As pointed out in another comment, this doesn't work when the link count is 0: $ uname -rv 4.15.0-3-amd64 #1 SMP Debian 4.15.17-1 (2018-04-19) $ touch f

As pointed out in another comment, this doesn't work when the link count is 0: $ uname -rv 4.15.0-3-amd64 #1 SMP Debian 4.15.17-1 (2018-04-19) $ touch foo $ exec 3<>foo $ rm foo $ ls -l /proc/$$/fd/3 lrwx------ 1 jwilk jwilk 64 Apr 25 10:02 /proc/324/fd/3 -> '/home/jwilk/foo (deleted)' $ strace -e linkat ln -L /proc/$$/fd/3 foo linkat(AT_FDCWD, "/proc/3447/fd/3", AT_FDCWD, "foo", AT_SYMLINK_FOLLOW) = -1 ENOENT (No such file or directory) ln: failed to create hard link 'foo' => '/proc/3447/fd/3': No such file or directory $ sudo strace -e linkat ln -L /proc/$$/fd/3 foo linkat(AT_FDCWD, "/proc/3447/fd/3", AT_FDCWD, "foo", AT_SYMLINK_FOLLOW) = -1 ENOENT (No such file or directory) ln: failed to create hard link 'foo' => '/proc/3447/fd/3': No such file or directory +++ exited with 1 +++