1.7.10 compatibility

apps/persist.lua

@@ -4,12 +4,19 @@ _G.requireInjector(_ENV)
 
 local Util = require('util')
 
+local fs    = _G.fs
 local shell = _ENV.shell
 
 local args = { ... }
-local fileName = args[1] or error('Syntax: persist <file name>')
+local fileName = args[1] and
+                 shell.resolve(args[1]) or
+                 error('Syntax: persist <file name>')
 
-local c = Util.readFile(shell.resolve(fileName)) or error('Unable to open file')
-Util.writeFile(shell.resolve(fileName), c)
+local c = Util.readFile() or error('Unable to read file')
+
+-- ensure it is writable - if not an error is thrown
+Util.writeFile(fileName, '')
+fs.delete(fileName)
+Util.writeFile(fileName, c)
 
 print('Saved')