$ sed -e :label -e N -e ‘s/\n/, /’ -e ‘s/[ |]//g’ -e tlabel <<xxxx
> |     919 |
> |    1027 |
> |    1593 |
> |    1595 |
> xxxx
919,1027,1593,1595

A: yum install sharutils

uuencode file.jpg file.jpg|mail -s “sending you this pretty picture” oops@domain.com

A: Or better yet install mutt

echo “My file”|mutt -a file.jpg -s “sending you this pretty picture” oops@domain.com

JAVA_OPTS=”-d64 -Xms512m -Xmx512m -XX:MaxPermSize=128m”
JAVA_OPTS=”-Djava.awt.headless=true -Djava.net.preferIPv4Stack=true $JAVA_OPTS”
JAVA_OPTS=”-verbose:gc -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:-TraceClassUnloading $JAVA_OPTS”
JAVA_OPTS=”-XX:+HeapDumpOnOutOfMemoryError -XX:+HeapDumpOnCtrlBreak -XX:HeapDumpPath=/home/tomcat/snapshots $JAVA_OPTS”

These are not good but they are working options to enable jmxremote console.

JAVA_OPTS=”-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.port=1888 -Djava.rmi.server.hostname=test.com  $JAVA_OPTS”
To exit on OutOfMemoryError in jdk1.6:

Unix:
-XX:OnOutOfMemoryError="kill -9 %p"

Windows:
-XX:OnOutOfMemoryError="taskkill /F /PID %p"

JRockIT:
-XXexitOnOutOfMemory

<Mar 12, 2009 12:35:34 PM EDT> <Info> <Management> <BEA-141107> <Version: WebLogic Server 10.3  Fri Jul 25 16:30:05 EDT 2008 1137967 >
<Mar 12, 2009 12:46:37 PM EDT> <Notice> <WebLogicServer> <BEA-000365> <Server state changed to STARTING>

Turns out Weblogic uses random number generator during start up. Because of the bug in java it reads ‘randomness’ from /dev/random. /dev/random is very good random numbers generators but it is extremely slow. It takes sometimes 10 minutes or more to generate one number. /dev/urandom is not that good, but it is instant.
Java somehow maps /dev/urandom file to /dev/random. That’s why default settings in $JAVA_HOME/jre/lib/security/java.security are useless.

Possible solutions:
1) Add  “-Djava.security.egd=file:/dev/./urandom” (/dev/urandom does not work) to java parameters.

Worse but working solution is:
2) mv /dev/random /dev/random.ORIG ; ln /dev/urandom /dev/random

3) Best solution is to change $JAVA_HOME/jre/lib/security/java.security
Replace securerandom.source with

securerandom.source=file:/dev/./urandom

This problem does not happen under windows because it uses different implementation of /dev/random.

It takes seconds to start weblogic server now.

strace ls 2>&1|grep “open”

[root@os]# netstat -nlp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State       PID/Program name
tcp        0      0 0.0.0.0:9921                0.0.0.0:*                   LISTEN      10982/ora_d000_orcl
tcp        0      0 10.10.10.10:1521           0.0.0.0:*                   LISTEN      12516/tnslsnr
tcp        0      0 0.0.0.0:22                  0.0.0.0:*                   LISTEN      6561/sshd
udp        0      0 127.0.0.1:1052              0.0.0.0:*                               10920/ora_pmon_orcl

Device is BLOCKED waiting to create a volume for:

It means that bacula ran out of volumes or space on disk and want you to create new volume manually.
Use “Label”, enter new volume name, assign it to a pool.
Your job should continue automatically.

find albums -name *.jpg -not -name *.sized.jpg -not -name *.thumb.jpg -not -name *.highlight.jpg -exec zip -r -1 album.zip {} ;&

use

find albums -name *.jpg -not -name *.sized.jpg -not -name *.thumb.jpg -not -name *.highlight.jpg -print| zip -1 album.zip -@

It will take 5 minutes instead of 5 hours on 500MB archive.

UseCanonicalName On

ServerName www.olegshpak.com
ServerAlias olegshpak.com
ServerAlias www.niteart.com
ServerAlias niteart.com

RewriteEngine on
RewriteCond %{REQUEST_METHOD} !^(GET|POST|HEAD)$
RewriteRule .* – [F]
RewriteCond %{HTTP_HOST} ^niteart.com$ [OR]
RewriteCond %{HTTP_HOST} ^www.niteart.com$ [OR]
RewriteCond %{HTTP_HOST} ^olegshpak.com$
RewriteRule ^(.*)$    http://%{SERVER_NAME}$1 [R=permanent,L]

If your configuration requires you to set UseCanonicalName to Off then use a real server name instead of variable in RewriteRule.

Why is it important? Main reason is SEO. With permanent redirect search engines are not going to think that you have two or more different websites with the same content.

Add to the end of /usr/local/java/jre/lib/logging.properties this line:

org.apache.tomcat.util.http.Parameters.level = SEVERE

Restart tomcat.

The reason for this message is some problem with url’s parameters format, like && in the begining of parameters etc. It is harmless, tomcat will process parameters anyway.

Another nice feature to reduce ammount of information in catalina.out file is to redirect system output from catalina.out to web application log. Add swallowOutput=”true” to the context like this:

[root@u tomcat]# more conf/Catalina/localhost/ROOT.xml
<Context docBase=”/clients/client1″
privileged=”true” antiResourceLocking=”false” antiJARLocking=”false”
swallowOutput=”true”>
</Context>