SetDirectory["/home/faculty/struther/public_html/Courses/5901"]
Data=Import["dummy-shadow"];
FixedData=Sort[
Table[ 
{s1,s2}=StringSplit[Data[[i]][[1]],":"];
StringJoin[{s2,":",s1}],
{i,1, Length[Data]}]
];
Export["Dump.txt",FixedData]