Installing Pig

To install Pig On RHEL-compatible systems:

$ sudo yum install pig

To install Pig on SLES systems:

$ sudo zypper install pig

To install Pig on Ubuntu and other Debian systems:

$ sudo apt-get install pig

To start Pig in interactive mode (YARN)

To start Pig, use the following command.

$ pig

To start Pig in interactive mode (MRv1)

Use the following command:

$ pig
You should see output similar to the following: 
2012-02-08 23:39:41,819 [main] INFO  org.apache.pig.Main - Logging error messages to: /home/user/pig-0.11.0-cdh5b1/bin/pig_1328773181817.log
2012-02-08 23:39:41,994 [main] INFO  org.apache.pig.backend.hadoop.executionengine.HExecutionEngine - Connecting to hadoop file system at: hdfs://hostname:8020
...
grunt>

Examples

If you don't already have sample data, create a file and load it to HDFS. For example:
  1. Create the file hostlist and enter the following data: 
    daily03.acme.com,123221991
daily04.acme.com,120222101
daily05.acme.com,119220077
fixed01.best.com,218880024
daily03.best.com,234320024
  2. Load hostlist to a user directory in HDFS, in this case the user cloudera. 
    $ hadoop fs -copyFromLocal hostlist /user/cloudera
At the Grunt shell, list the HDFS directory: 
grunt> ls hdfs://hostname:8020/user/cloudera

hdfs://hostname:8020/user/cloudera/hostlist
To run a grep example job using Pig for grep inputs: 
grunt> A = LOAD 'hostlist' AS (host:chararray, capacity:int);

DUMP A;
(daily03.acme.com,123221991)
(daily04.acme.com,120222101)
(daily05.acme.com,119220077)
(fixed01.best.com,218880024)
(fixed02.best.com,234320024)

grunt> B = FILTER A BY $0 MATCHES '.*best.*';
grunt> DUMP B;

(fixed01.best.com,218880024)
(daily03.best.com,234320024)