大數據-01-hadoop-03-HDFS的Shell操做（開發重點）

HDFS的Shell操做（開發重點）

1．基本語法

bin/hadoop fs 具體命令   OR  bin/hdfs dfs 具體命令

dfs是fs的實現類。

2．命令大全

[atguigu@hadoop102 hadoop-2.7.2]$ bin/hadoop fs

 

[-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 ...]]

3．經常使用命令實操

（0）啓動Hadoop集羣（方便後續的測試）

[atguigu@hadoop102 hadoop-2.7.2]$ sbin/start-dfs.sh

[atguigu@hadoop103 hadoop-2.7.2]$ sbin/start-yarn.sh

（1）-help：輸出這個命令參數

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -help rm

（2）-ls: 顯示目錄信息

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -ls /

（3）-mkdir：在HDFS上建立目錄

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -mkdir -p /sanguo/shuguo

（4）-moveFromLocal：從本地剪切粘貼到HDFS

[atguigu@hadoop102 hadoop-2.7.2]$ touch kongming.txt

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs  -moveFromLocal  ./kongming.txt  /sanguo/shuguo

（5）-appendToFile：追加一個文件到已經存在的文件末尾

[atguigu@hadoop102 hadoop-2.7.2]$ touch liubei.txt

[atguigu@hadoop102 hadoop-2.7.2]$ vi liubei.txt

輸入

san gu mao lu

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -appendToFile liubei.txt /sanguo/shuguo/kongming.txt

（6）-cat：顯示文件內容

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -cat /sanguo/shuguo/kongming.txt

（7）-chgrp 、-chmod、-chown：Linux文件系統中的用法同樣，修改文件所屬權限

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs  -chmod  666  /sanguo/shuguo/kongming.txt

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs  -chown  atguigu:atguigu   /sanguo/shuguo/kongming.txt

（8）-copyFromLocal：從本地文件系統中拷貝文件到HDFS路徑去

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -copyFromLocal README.txt /

（9）-copyToLocal：從HDFS拷貝到本地

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -copyToLocal /sanguo/shuguo/kongming.txt ./

（10）-cp ：從HDFS的一個路徑拷貝到HDFS的另外一個路徑

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -cp /sanguo/shuguo/kongming.txt /zhuge.txt

（11）-mv：在HDFS目錄中移動文件

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -mv /zhuge.txt /sanguo/shuguo/

（12）-get：等同於copyToLocal，就是從HDFS下載文件到本地

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -get /sanguo/shuguo/kongming.txt ./

（13）-getmerge：合併下載多個文件，好比HDFS的目錄 /user/atguigu/test下有多個文件:log.1, log.2,log.3,...

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -getmerge /user/atguigu/test/* ./zaiyiqi.txt

（14）-put：等同於copyFromLocal

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -put ./zaiyiqi.txt /user/atguigu/test/

（15）-tail：顯示一個文件的末尾

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -tail /sanguo/shuguo/kongming.txt

（16）-rm：刪除文件或文件夾

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -rm /user/atguigu/test/jinlian2.txt

（17）-rmdir：刪除空目錄

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -mkdir /test

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -rmdir /test

（18）-du統計文件夾的大小信息

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -du -s -h /user/atguigu/test

2.7 K  /user/atguigu/test

 

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -du  -h /user/atguigu/test

1.3 K  /user/atguigu/test/README.txt

15     /user/atguigu/test/jinlian.txt

1.4 K  /user/atguigu/test/zaiyiqi.txt

（19）-setrep：設置HDFS中文件的副本數量

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -setrep 10 /sanguo/shuguo/kongming.txt

圖3-3  HDFS副本數量

這裏設置的副本數只是記錄在NameNode的元數據中，是否真的會有這麼多副本，還得看DataNode的數量。由於目前只有3臺設備，最多也就3個副本，只有節點數的增長到10臺時，副本數才能達到10。