@Rohan44
A simple one liner could help here:
for i in $(hdfs dfs -ls -R /tmp/| awk '{print $8}'| grep [A-Z] ); do hdfs dfs -mv $i `echo $i | tr 'A-Z' 'a-z'`; done
In this example I have directories with upper case names under /tmp.
/tmp/MONTH=07/DAY=31/HOUR=00
As I am using a simple `mv`, when it renames the parent directory, it will fail to rename the child directories.
So, you might see 'no such file or directory' errors. But, run the same command a couple of times based on the depth of your partition directories. Run it as hdfs superuser.