Daniel, You can find those std out statements in "{LOG Directory}/userlogs/{task attemp id}/stdout" file.
Same way you can find std err statements in "{LOG Directory}/userlogs/{task attemp id}/stderr" and log statements in "{LOG Directory}/userlogs/{task attemp id}/syslog". Devaraj K -----Original Message----- From: Daniel,Wu [mailto:hadoop...@163.com] Sent: Thursday, July 28, 2011 11:47 AM To: common-user@hadoop.apache.org Subject: where to find the log info Hi everyone, I am new to it, and want to do some debug/log. I'd like to check what the value is for each mapper execution. If I add the following code in bold, where can I find the log info? If I can't do it in this way, how should I do? public void map(Object key, Text value, Context context ) throws IOException, InterruptedException { StringTokenizer itr = new StringTokenizer(value.toString()); System.out.println(value.toString); while (itr.hasMoreTokens()) { word.set(itr.nextToken()); context.write(word, one); } } }