在搭建环境的过程中我们用过: 以 hadoop fs 表示file system 开头
查询所有的hdfs shell命令
[root@localhost current]# hadoop fs Usage: hadoop fs [generic options] [-appendToFile <localsrc> ... <dst>] [-cat [-ignoreCrc] <src> ...] [-checksum <src> ...] [-chgrp [-R] GROUP PATH...] [-chmod [-R] <MODE[,MODE]... | OCTALMODE> PATH...] [-chown [-R] [OWNER][:[GROUP]] PATH...] [-copyFromLocal [-f] [-p] <localsrc> ... <dst>] [-copyToLocal [-p] [-ignoreCrc] [-crc] <src> ... <localdst>] [-count [-q] <path> ...] [-cp [-f] [-p] <src> ... <dst>] [-createSnapshot <snapshotDir> [<snapshotName>]] [-deleteSnapshot <snapshotDir> <snapshotName>] [-df [-h] [<path> ...]] [-du [-s] [-h] <path> ...] [-expunge] [-get [-p] [-ignoreCrc] [-crc] <src> ... <localdst>] [-getfacl [-R] <path>] [-getmerge [-nl] <src> <localdst>] [-help [cmd ...]] [-ls [-d] [-h] [-R] [<path> ...]] [-mkdir [-p] <path> ...] [-moveFromLocal <localsrc> ... <dst>] [-moveToLocal <src> <localdst>] [-mv <src> ... <dst>] [-put [-f] [-p] <localsrc> ... <dst>] [-renameSnapshot <snapshotDir> <oldName> <newName>] [-rm [-f] [-r|-R] [-skipTrash] <src> ...] [-rmdir [--ignore-fail-on-non-empty] <dir> ...] [-setfacl [-R] [{-b|-k} {-m|-x <acl_spec>} <path>]|[--set <acl_spec> <path>]] [-setrep [-R] [-w] <rep> <path> ...] [-stat [format] <path> ...] [-tail [-f] <file>] [-test -[defsz] <path>] [-text [-ignoreCrc] <src> ...] [-touchz <path> ...] [-usage [cmd ...]] Generic options supported are -conf <configuration file> specify an application configuration file -D <property=value> use value for given property -fs <local|namenode:port> specify a namenode -jt <local|jobtracker:port> specify a job tracker -files <comma separated list of files> specify comma separated files to be copied to the map reduce cluster -libjars <comma separated list of jars> specify comma separated jar files to include in the classpath. -archives <comma separated list of archives> specify comma separated archives to be unarchived on the compute machines. The general command line syntax is bin/hadoop command [genericOptions] [commandOptions]
注意:hdfs对于文件不允许修改，但是可以对内容进行追加，修改的时候需要将前面分好的块进行重新排列，所以不支持，但是追加可以实现，相当于重新加块。
注意: 对于hadoop命令，/相当于hdfs的根目录，不是linux的根目录。当然也可以全写 hdfs://localhost:9000/
例如:列出文件夹结构: -ls
^C[root@localhost current]# hadoop fs -ls / Found 4 items -rw-r--r-- 1 root supergroup 37667 2018-04-11 03:29 /install.log drwx------ - root supergroup 0 2018-04-11 03:54 /tmp drwxr-xr-x - root supergroup 0 2018-04-11 03:54 /user drwxr-xr-x - root supergroup 0 2018-04-11 04:10 /wordcount
类似于linux的ls，可以看出文件类型与权限。1代表在集群中的备份数量。
修改文件所属主: -chown
[root@localhost current]# hadoop fs -chown hadoop /install.log [root@localhost current]# hadoop fs -ls / Found 4 items -rw-r--r-- 1 hadoop supergroup 37667 2018-04-11 03:29 /install.log drwx------ - root supergroup 0 2018-04-11 03:54 /tmp drwxr-xr-x - root supergroup 0 2018-04-11 03:54 /user drwxr-xr-x - root supergroup 0 2018-04-11 04:10 /wordcount
修改权限: -chmod
[root@localhost current]# hadoop fs -chmod 777 /install.log [root@localhost current]# hadoop fs -ls / Found 4 items -rwxrwxrwx 1 hadoop supergroup 37667 2018-04-11 03:29 /install.log drwx------ - root supergroup 0 2018-04-11 03:54 /tmp drwxr-xr-x - root supergroup 0 2018-04-11 03:54 /user drwxr-xr-x - root supergroup 0 2018-04-11 04:10 /wordcount
文件上传: -copyFromLocal (相当于 -put )
[root@localhost ~]# hadoop fs -copyFromLocal ./anaconda-ks.cfg / [root@localhost ~]# hadoop fs -ls / Found 5 items -rw-r--r-- 1 root supergroup 2388 2018-04-11 05:30 /anaconda-ks.cfg -rwxrwxrwx 1 hadoop supergroup 37667 2018-04-11 03:29 /install.log drwx------ - root supergroup 0 2018-04-11 03:54 /tmp drwxr-xr-x - root supergroup 0 2018-04-11 03:54 /user drwxr-xr-x - root supergroup 0 2018-04-11 04:10 /wordcount
文件下载 -copyToLocal (相当于 -get ）
[root@localhost test]# hadoop fs -get /install.log [root@localhost test]# ls install.log [root@localhost test]# hadoop fs -copyToLocal /anaconda-ks.cfg [root@localhost test]# ls anaconda-ks.cfg install.log
文件复制:-cp (直接从hdfs中复制)
[root@localhost test]# hadoop fs -cp /install.log /wordcount/ [root@localhost test]# hadoop fs -ls / Found 5 items -rw-r--r-- 1 root supergroup 2388 2018-04-11 05:30 /anaconda-ks.cfg -rwxrwxrwx 1 hadoop supergroup 37667 2018-04-11 03:29 /install.log drwx------ - root supergroup 0 2018-04-11 03:54 /tmp drwxr-xr-x - root supergroup 0 2018-04-11 03:54 /user drwxr-xr-x - root supergroup 0 2018-04-11 05:35 /wordcount [root@localhost test]# hadoop fs -ls /wordcount/ Found 3 items drwxr-xr-x - root supergroup 0 2018-04-11 04:08 /wordcount/input -rw-r--r-- 1 root supergroup 37667 2018-04-11 05:35 /wordcount/install.log drwxr-xr-x - root supergroup 0 2018-04-11 04:10 /wordcount/output
查看目录与文件大小: -du
[root@localhost test]# hadoop fs -du -s -h hdfs://localhost:9000/* #查看根目录下每个文件夹与文件的大小(这里需要写全路径) 2.3 K hdfs://localhost:9000/anaconda-ks.cfg 36.8 K hdfs://localhost:9000/install.log 269.6 K hdfs://localhost:9000/tmp 0 hdfs://localhost:9000/user 36.8 K hdfs://localhost:9000/wordcount
创建目录: -mkdir (不会递归创建目录)
[root@localhost test]# hadoop fs -mkdir /aa [root@localhost test]# hadoop fs -ls / Found 6 items drwxr-xr-x - root supergroup 0 2018-04-11 05:58 /aa -rw-r--r-- 1 root supergroup 2388 2018-04-11 05:30 /anaconda-ks.cfg -rwxrwxrwx 1 hadoop supergroup 37667 2018-04-11 03:29 /install.log drwx------ - root supergroup 0 2018-04-11 03:54 /tmp drwxr-xr-x - root supergroup 0 2018-04-11 03:54 /user drwxr-xr-x - root supergroup 0 2018-04-11 05:35 /wordcount
删除文件与文件夹: -rm (删除文件夹需要加-r参数，表示递归删除)
[root@localhost test]# hadoop fs -rm -f /anaconda-ks.cfg
[root@localhost test]# hadoop fs -rm -f -r /aa
移动文件:从本地移到hdfs，从hdfs移到本地，在hdfs中移动
[-moveFromLocal <localsrc> ... <dst>] [-moveToLocal <src> <localdst>] [-mv <src> ... <dst>]
观察尾部日志与实时刷新日志:(类似于linux的tail -f)
[-tail [-f] <file>]
常见的几个命令:
1.0查看帮助 hadoop fs -help <cmd> 1.1上传 hadoop fs -put <linux上文件> <hdfs上的路径> 1.2查看文件内容 hadoop fs -cat <hdfs上的路径> 1.3查看文件列表 hadoop fs -ls / 1.4下载文件 hadoop fs -get <hdfs上的路径> <linux上文件>
【当你用心写完每一篇博客之后,你会发现它比你用代码实现功能更有成就感!】
