QNX4 operating system using Korn Shell. This is in a .profile file.

export VARDIR=//1/usr/pvcs

What does the //1/ represent?


For the most part, multiple slashes are equivalent to a single slash. There's one exception: paths beginning with exactly two slashes (//foo/…, as opposed to /foo/… or ///foo/…) have a different meaning on some Unix variants. The meaning is often to access a remote resource with a path like //hostname/dir1/dir2/dir3/file. (Windows does this too, with \\hostname\dir1\dir2\dir3\file.)

QNX is one of those variants. On QNX4 with the FLEET distributed processing protocol, // followed by a number refers to that node. So //1/usr/pvcs on any node refers to the file /usr/pvcs on node 1.

(Source: the QNX6 manual, I can't find official QNX4 documentation online.)


To all indications, the variable is receiving a web path as content.

//aaaa/bbbb/cccc/nnnn - 
at where: 
aaaa = server name or IP address; 
bbbb = folder from the logical root of the domain aaaa (web servers can handle this dynamically); 
cccc = bbbb subfolder; 
nnnn = nth subfolder.
  • 3
    It is not an URL, but a special path handled in a particular way on QNX systems. – Kusalananda Feb 7 '18 at 10:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.