How to find the blocks/chunks of a file in HDFS?

We know that HDFS stores a file by splitting it in multiples blocks or chunks based on the configured block size property. The blocks of a file are replicated for fault tolerance based on the replication factor configuration.

But how we can find the locations of these blocks and the nodes these blocks are replicated? It might be required in case of any maintenance activity and we need to shutdown few data nodes. Also for the data locality to know the exact location of the data in cluster.

The following fsck command of hadoop can be used to find the blocks and the location of the blocks:

 $ hadoop fsck /test -files -blocks -locations -racks  
 FSCK started by hadoop from /10.58.127.50 for path /test at Sun Jan 06 01:04:00 IST 2013  
 /test <dir>  
 /test/README.txt 1366 bytes, 1 block(s): OK  
 0. blk_606611195878801492_2473688 len=1366 repl=3 [/default-rack/10.58.127.59:50010, /default-rack/10.58.127.57:50010, /default-rack/10.58.127.51:50010]  
 Status: HEALTHY  
  Total size: 1366 B  
  Total dirs: 1  
  Total files: 1  
  Total blocks (validated): 1 (avg. block size 1366 B)  
  Minimally replicated blocks: 1 (100.0 %)  
  Over-replicated blocks: 0 (0.0 %)  
  Under-replicated blocks: 0 (0.0 %)  
  Mis-replicated blocks: 0 (0.0 %)  
  Default replication factor: 3  
  Average block replication: 3.0  
  Corrupt blocks: 0  
  Missing replicas: 0 (0.0 %)  
  Number of data-nodes: 9  
  Number of racks: 1  
 FSCK ended at Sun Jan 06 01:04:00 IST 2013 in 0 milliseconds  
 The filesystem under path '/test' is HEALTHY  

The above output shows that in the /test folder the file README.txt has only 1 blocks with replication factor 3 and also shows the ip addresses of the slave nodes.