forgot to commit openos

data/openos/bin/umount.lua

@@ -0,0 +1,37 @@
+local fs = require("filesystem")
+local shell = require("shell")
+
+local args, options = shell.parse(...)
+
+if #args < 1 then
+  io.write("Usage: umount [-a] <mount>\n")
+  io.write(" -a  Remove any mounts by file system label or address instead of by path. Note that the address may be abbreviated.\n")
+  return 1
+end
+
+local proxy, reason
+if options.a then
+  proxy, reason = fs.proxy(args[1])
+  if proxy then
+    proxy = proxy.address
+  end
+else
+  local path = shell.resolve(args[1])
+  proxy, reason = fs.get(path)
+  if proxy then
+    proxy = reason -- = path
+    if proxy ~= path then
+      io.stderr:write("not a mount point\n")
+      return 1
+    end
+  end
+end
+if not proxy then
+  io.stderr:write(tostring(reason)..'\n')
+  return 1
+end
+
+if not fs.umount(proxy) then
+  io.stderr:write("nothing to unmount here\n")
+  return 1
+end