输入hadoop jar ~/hadoop-2.7.7/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.7.jar pi 10 10
之后！！！
出现了：
root@master ~]# start-all.sh
This script is Deprecated. Instead use start-dfs.sh and start-yarn.sh
Incorrect configuration: namenode address dfs.namenode.servicerpc-address or dfs.nam
Starting namenodes on []
The authenticity of host 'localhost (::1)' can't be established.
ECDSA key fingerprint is SHA256:4DQK5+akq6UcZ77DnOfz/Tg6JyFuLaMo4rGptYJZIpc.
ECDSA key fingerprint is MD5:12:ef:c7:b5:11:0e:e6:c7:6d:4c:f6:6e:5c:4b:7e:a0.
Are you sure you want to continue connecting (yes/no)? s2: Error: JAVA_HOME is not s
s1: Error: JAVA_HOME is not set and could not be found.
然后就一行错一行的改
但是！
一个也没改出来！
我就从Xshall开始重复了三遍
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嗯。最后才知道输入yes继续往下走就可以了