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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "ShellScriptProgrammingGuide" by SomeOtherAccount
Date Tue, 15 Jul 2014 17:34:07 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "ShellScriptProgrammingGuide" page has been changed by SomeOtherAccount:
https://wiki.apache.org/hadoop/ShellScriptProgrammingGuide?action=diff&rev1=10&rev2=11

Comment:
More on env vars

  
   * A decent shell lint is available at http://www.shellcheck.net .  Mac users can `brew
install shellcheck` to install it locally. Like lint, however, be aware that it will sometimes
flag things that are legitimate.   
  
+ = Standard Environment Variables =
+ 
+ In addition to all of the variables documented in `*-env.sh` and `hadoop-layout.sh`, there
are a handful of special env vars:
+ 
+ * JAVA_HEAP_MAX - This is the Xmx parameter to be passed to Java. (e.g., `"-Xmx1g"`).  This
is present for backward compatibility, however it should be added to HADOOP_OPTS via `hadoop_add_param
HADOOP_OPTS Xmx "${JAVA_HEAP_MAX}"` prior to calling `hadoop_finalize`.
+ 
+ * HADOOP_DAEMON_MODE - This will be set to `start` or `stop` based upon what `hadoop-config.sh`
has determined from the command line options.
+ 
+ * HADOOP_LOGFILE - This sets hadoop.log.file, which in turn will go to log4j.  In many cases,
you'll want to modify this based upon the daemon.
+ 
+ * HADOOP_SECURE_USER - This should be set to the user that should be running your secure
daemon.  This '''MUST''' be set prior to calling the `hadoop_secure_*` functions.
+ 
+ * HADOOP_SLAVES - This is the file name the user passed via `--hosts`.
+ 
+ * HADOOP_SLAVE_NAMES - This is the list of hosts the user passed via `--hostnames`.
+ 

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