topic java command and grep on output in Operating System - Linux

java command and grep on output

Leo The Cat — Mon, 07 Dec 2009 16:22:49 GMT

Hello

I'd like to save the result of a java ksh command. This command normally show something likke that:

java.sql.SQLException: ORA-01017: invalid username/password; logon denied

at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331)
at oracle.jdbc.driver.T4CTTIoer.processErr

....

Example: java -jar test.jar | tee -a /tmp/test.tmp

The full result comes on screen but no lines in the /tmp file.

why ?
I think that it's somewhere a problem with standard output but how to do the trick !

Thanks in advance
Bests Regards
Den

Re: java command and grep on output

Matti_Kurkela — Mon, 07 Dec 2009 17:12:37 GMT

Perhaps the missing messages are not sent to standard output stream (stdout, file descriptor #1), but to standard error stream (stderr, file descriptor #2).

If you wish to capture both, try a command like:

java -jar test.jar 2>&1 | tee -a /tmp/test.tmp

The "2>&1" merges the standard error stream to the output stream, so that the content of both streams can be received by the pipe.

(Nitpick: "java" is not a ksh command, as it is not specific to ksh in any way, nor built in to it. It's a wholly independent program binary, more specifically a Java bytecode interpreter/JIT compiler. It is most commonly known as JVM = Java Virtual Machine.)

MK

Re: java command and grep on output

Leo The Cat — Mon, 07 Dec 2009 18:32:45 GMT

Thanks Matti, efficient answer !