diff --git a/pbatch/pb.rb b/pbatch/pb.rb
index 70029d6..55d7e59 100755
--- a/pbatch/pb.rb
+++ b/pbatch/pb.rb
@@ -39,20 +39,22 @@ ENDTXT
 end
 
 def readconfig
-	File.open("#{@basedir}/#{CONFIG}").each_line {|line|
-		line.sub!(/#.*/, "")
-		line.sub!(/^\s*/, "")
-		line.sub!(/\s*$/, "")
-		if line.match(/^$/)
-			next
-		end
-		line.match(/([^=]*?)\s*=\s*(.*)/)
-		case $1
-			when "maxproc"		then @config["maxproc"] = $2
-			when "waittime"		then @config["waittime"] = $2
-			else			puts "unknown option #{$1}"
-		end
-	}
+	if FileTest.exists?("#{@basedir}/#{CONFIG}")
+		File.open("#{@basedir}/#{CONFIG}").each_line {|line|
+			line.sub!(/#.*/, "")
+			line.sub!(/^\s*/, "")
+			line.sub!(/\s*$/, "")
+			if line.match(/^$/)
+				next
+			end
+			line.match(/([^=]*?)\s*=\s*(.*)/)
+			case $1
+				when "maxproc"		then @config["maxproc"] = $2
+				when "waittime"		then @config["waittime"] = $2
+				else			puts "unknown option #{$1}"
+			end
+		}
+	end
 end
 
 def status
@@ -111,7 +113,7 @@ def addjob
 		puts "Job #{jobnumber} already scheduled. This should not happen."
 		exit
 	end
-	File.open("#{@basedir}/#{JOBSDIR}/#{jobnumber}"){|file|
+	File.open("#{@basedir}/#{JOBSDIR}/#{jobnumber}", "w"){|file|
 		file.puts ARGV.join(" ")
 	}
 	File.chmod(RUNMODE, "#{@basedir}/#{JOBSDIR}/#{jobnumber}")
@@ -136,7 +138,7 @@ end
 
 def createconfig
 	if ! FileTest.exists?("#{@basedir}/#{CONFIG}")
-		File.new("#{@basedir}/#{CONFIG}", "w"){|file|
+		File.open("#{@basedir}/#{CONFIG}", "w"){|file|
 			file.puts <<EOT
 # how many parallel processes?
 maxproc=3
@@ -149,7 +151,7 @@ end
 
 def master
 	# als ik threading ga gebruiken is deze dus niet nodig
-	File.new(RUNNINGFILE, "w").flock(File::LOCK_EX){|file|
+	File.open(RUNNINGFILE, "w").flock(File::LOCK_EX){|file|
 		file.puts "0"
 	}