本篇内容介绍了“pig的基本操作介绍”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
pig是什么？
我的理解是： pig就相当于 shell , hadoop就相当于linux (所以我尽可能的会使用pig操作hadoop的文件)
1.进入HADOOP_HOME目录。
2.执行sh bin/hadoop
我们可以看到更多命令的说明信息：
Usage: hadoop [–config confdir] COMMAND
where COMMAND is one of:
namenode -format format the DFS filesystem
secondarynamenode run the DFS secondary namenode
namenode run the DFS namenode
datanode run a DFS datanode
dfsadmin run a DFS admin client
fsck run a DFS filesystem checking utility
fs run a generic filesystem user client
balancer run a cluster balancing utility
jobtracker run the MapReduce job Tracker node
pipes run a Pipes job
tasktracker run a MapReduce task Tracker node
job manipulate MapReduce jobs
queue get information regarding JobQueues
version print the version
jar <jar> run a jar file
distcp <srcurl> <desturl> copy file or directories recursively
archive -archiveName NAME <src>* <dest> create a hadoop archive
daemonlog get/set the log level for each daemon
or
CLASSNAME run the class named CLASSNAME
Most commands print help when invoked w/o parameters.
常用pig命令
ls/ pwd/ cd
例如： 查看文件大小
grunt> fs -du -h -s 文件名
19.4 G 文件名
grunt> help
Commands:
<pig latin statement>; – See the PigLatin manual for details: http://hadoop.apache.org/pig
File system commands:
fs <fs arguments> – Equivalent to Hadoop dfs command: http://hadoop.apache.org/common/docs/current/hdfs_shell.html
Diagnostic commands:
describe <alias>[::<alias] – Show the schema for the alias. Inner aliases can be described as A::B.
explain [-script <pigscript>] [-out <path>] [-brief] [-dot|-xml] [-param <param_name>=<param_value>]
[-param_file <file_name>] [<alias>] – Show the execution plan to compute the alias or for entire script.
-script – Explain the entire script.
-out – Store the output into directory rather than print to stdout.
-brief – Don't expand nested plans (presenting a smaller graph for overview).
-dot – Generate the output in .dot format. Default is text format.
-xml – Generate the output in .xml format. Default is text format.
-param <param_name – See parameter substitution for details.
-param_file <file_name> – See parameter substitution for details.
alias – Alias to explain.
dump <alias> – Compute the alias and writes the results to stdout.
Utility Commands:
exec [-param <param_name>=param_value] [-param_file <file_name>] <script> –
Execute the script with access to grunt environment including aliases.
-param <param_name – See parameter substitution for details.
-param_file <file_name> – See parameter substitution for details.
script – Script to be executed.
run [-param <param_name>=param_value] [-param_file <file_name>] <script> –
Execute the script with access to grunt environment.
-param <param_name – See parameter substitution for details.
-param_file <file_name> – See parameter substitution for details.
script – Script to be executed.
sh <shell command> – Invoke a shell command.
kill <job_id> – Kill the hadoop job specified by the hadoop job id.
set <key> <value> – Provide execution parameters to Pig. Keys and values are case sensitive.
The following keys are supported:
default_parallel – Script-level reduce parallelism. Basic input size heuristics used by default.
debug – Set debug on or off. Default is off.
job.name – Single-quoted name for jobs. Default is PigLatin:<script name>
job.priority – Priority for jobs. Values: very_low, low, normal, high, very_high. Default is normal
stream.skippath – String that contains the path. This is used by streaming.
any hadoop property.
help – Display this message.
history [-n] – Display the list statements in cache.
-n Hide line numbers.
quit – Quit the grunt shell.
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