我在哪里可以找到下面提到的示例程序的详细文档，但我在文档中找不到。
hduser@canberra:~/work/software/cloudera/hadoop-2.0.0-cdh4.0.0$ hadoop jar src/hadoop-mapreduce-project/hadoop-mapreduce-examples/target/hadoop-mapreduce-examples-2.0.0-cdh4.0.0.jar
An example program must be given as the first argument.
Valid program names are:
aggregatewordcount: An Aggregate based map/reduce program that counts the words in the input files.
aggregatewordhist: An Aggregate based map/reduce program that computes the histogram of the words in the input files.
bbp: A map/reduce program that uses Bailey-Borwein-Plouffe to compute exact digits of Pi.
dbcount: An example job that count the pageview counts from a database.
distbbp: A map/reduce program that uses a BBP-type formula to compute exact bits of Pi.
grep: A map/reduce program that counts the matches of a regex in the input.
join: A job that effects a join over sorted, equally partitioned datasets
multifilewc: A job that counts words from several files.
pentomino: A map/reduce tile laying program to find solutions to pentomino problems.
pi: A map/reduce program that estimates Pi using a quasi-Monte Carlo method.
randomtextwriter: A map/reduce program that writes 10GB of random textual data per node.
randomwriter: A map/reduce program that writes 10GB of random data per node.
secondarysort: An example defining a secondary sort to the reduce.
sort: A map/reduce program that sorts the data written by the random writer.
sudoku: A sudoku solver.
teragen: Generate data for the terasort
terasort: Run the terasort
teravalidate: Checking results of terasort
wordcount: A map/reduce program that counts the words in the input files.
AFAIK，没有针对所有示例的单独文档。因此，代码是唯一的信息来源。
首先，必须从ExampleDriver.java中找到有效程序名（distbbp）和java类（o.a.h.examples.pi.distbbp）之间的关联。在大多数情况下，实际的代码（o.a.h.examples.pi.DistBP）都有要发送的参数和注释中的描述，如果没有，请查看代码。