快速學習-HDFS的Shell操作
- 2020 年 2 月 19 日
- 筆記
第2章 HDFS的Shell操作（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．常用命令實操
（0）啟動Hadoop集群（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: 顯示目錄資訊
[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -ls /
（3）-mkdir：在HDFS上創建目錄
[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文件系統中的用法一樣，修改文件所屬許可權
[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，比如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統計文件夾的大小資訊
[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
這裡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。因為目前只有3台設備，最多也就3個副本，只有節點數的增加到10台時，副本數才能達到10。
