How to drop a DB2 instance if instance owner does not exist anymore

Let's say that your instance owner was user db2inst1 and you removed it via OS tools. When you want to uninstall DB2 it complains that you have to drop db2inst1 instance. Running db2idrop gives you error, since user db2inst1 does not exist anymore. In this case you can use this:

db2greg -delinstrec instancename=db2inst1

db2greg is a nice tool that lets you display and alter global registry. More at DB2 10.1 Info Center

Enable hibernate in Ubuntu 13.04

Follow these steps:
- open terminal
- sudo vi /var/lib/polkit-1/localauthority/50-local.d/hibernate.pkla
- paste these lines:

[Re-enable Hibernate]

Identity=unix-user:*

Action=org.freedesktop.upower.hibernate

ResultActive=yes

- reboot

NetBeans in maximized mode on Ubuntu 13.04

Today I upgraded my laptop (Dell Latitude E5520) to Ubuntu 13.04.
On there I'm also running NetBeans 7.3.1 on JDK 1.7.0_25. The problem I had was that when I maximized NetBeans the content of the window was not refreshed.
After testing several settings I found that setting sun.java2d.opengl=false fixed the problem.

Laptop is using Intel graphics card with a i915 driver. Maybe there is some kind of a problem between this setting and Java. I don't know.

Mouse not working after suspend in Ubuntu 12.04

If you mouse is now working after computer gets back from suspend try this:

• sudo vi /etc/pm/sleep.d/20_custom-ehci_hcd:

#!/bin/sh
# File: "/etc/pm/sleep.d/20_custom-ehci_hcd".
TMPLIST=/tmp/ehci-dev-list
case "${1}" in
        hibernate|suspend)
        ;;
        resume|thaw)
     chvt 1
     chvt 7
        ;;
esac

• sudo chmod 755 /etc/pm/sleep.d/20_custom-ehci_hcd 

Initialize DB2 environment in cmd

Usually when I want to work with DB2 on Windows I run db2cmd, so the DB2 environment gets initialized. However this does not work if I'm connected to a Windows machine via SSH, since db2cmd opens new cmd window.
Solution to this problem is typing "db2cmd -i -w db2clpsetcp" in cmd. Wihout quotes of course.

Ubuntu: Make F10 work in Midnight Commander

If you are using Unity and Midnight Commander in gnome-terminal then F10 gets send to the terminal program not the Midnight Commander.

Here are the steps to correct this:

1. install compizconfig-settings-manager
2. run it
3. go to "Ubuntu Unity plugin"
4. disable "Key to open first panel menu"
5. go to terminal menu Edit - keyboard shortcuts and disable "Enable the menu shortcut key (F10 by default)"
6. paste this code into terminal (https://bugs.launchpad.net/ubuntu/+source/unity/+bug/726639/comments/18):

mkdir -p ~/.config/gtk-3.0
cat< ~/.config/gtk-3.0/gtk.css

@binding-set NoKeyboardNavigation {
     unbind "F10"
}

* {
     gtk-key-bindings: NoKeyboardNavigation
}

EOF

Ubuntu: How to change the location of various default directories

If you want to change the location of the Desktop, Documents, Download, ... directories:

vi ~/.config/user-dirs.dirs

Finding bad blocks on hard drive in Linux

Run:

• sudo badblocks -v /dev/sda1 > bad.block
• sudo fsck -t ext4 -l bad.block /dev/sda1

badblocks is part of the e2fsprogs package in Ubuntu. The first command will find all bad blocks that you may have on /dev/sda1 and the second one will try to move data found in bad blocks to another place. If it can't then the file may be corrupted and lost.

Pass all script arguments to another script

When you want to pass all the input arguments to another script or program you can do it like this:

• in bash use "$@"
• in bat use %*

From Kubuntu to Ubuntu

Steps:

• sudo apt-get install ubuntu_desktop
• change display manager to lightdm as described in Change Linux display manager
• change lightdm greeter theme as described in Change lightdm greeter theme
• set ubuntu boot splash screen:
• sudo update-alternatives --set default.plymouth /lib/plymouth/themes/ubuntu-logo/ubuntu-logo.plymouth
• sudo update-alternatives --set text.plymouth /lib/plymouth/themes/ubuntu-text/ubuntu-text.plymouth

Change Linux display manager

You can have mulitple diplay manager installed at any time:

• gdm
• lightdm
• kdm

You can switch between them:

• if you have gdm running then use

sudo dpkg-reconfigure gdm

• if you have kdm running then use

sudo dpkg-reconfigure kdm 

• if you have lightdm running then use

sudo dpkg-reconfigure lightdm

Change lightdm greeter theme

Run

sudo vim /etc/lightdm/lightdm.conf

and change

greeter-session=unity-greeter

to

greeter-session=lightdm-gtk-greeter

or something. There are multiply *-greeter packages you can install and use

Disable scrollbar overlay in Ubuntu

In 12.04:
gsettings set org.gnome.desktop.interface ubuntu-overlay-scrollbars false

In 12.10:

gsettings set com.canonical.desktop.interface scrollbar-mode normal

And to return to the default settings:
gsettings reset com.canonical.desktop.interface scrollbar-mode

All commands are run from console

Touchscreen calibration under Linux

If you have a touchscreen and want to caibrate it follow this steps:

• sudo apt-get install xinput-calibrator
• run it. You can run it from console or find it somewhere in your menu
• after calibration you will get an output in your console and the line you should copy looks something like this:
  Option "Calibration" "77 3935 115 3984"
• sudo vi /usr/share/X11/xorg.conf.d/10-evdev.conf and copy previous line in touchscreen section:
  Section "InputClass"        Identifier "evdev touchscreen catchall"        MatchIsTouchscreen "on"        MatchDevicePath "/dev/input/event*"        Driver "evdev"        Option "Calibration" "77 3935 115 3984"EndSection

I've used xinput_calibrator on Ubuntu 10.11 and 12.04.

Where is GRUB installed on Linux system

If you want to know that use script located at http://bootinfoscript.sourceforge.net/

2013

I wish a happy new year 2013 to all of you out there.

Running sudo command without password

What I found out is that running a command using sudo without entering password there are two options:

• echo PASSWORD | sudo -S COMMAND
• adding following lineto /etc/sudoers:

username ALL=(ALL) NOPASSWD: COMMAND

Please note that this has to be after all group definitions.
You can check what sudo priviliges you have using

sudo -l

For this case this gives:

(ALL) ALL
(ALL) NOPASSWD: COMMAND 

This means that all command require password except for the COMMAND. If we would put the username definitin before group definitions sudo -l would give:

(ALL) NOPASSWD: COMMAND
(ALL) ALL

This would still require password for all commands.

Find where code was changed in Mercurial

If you want to find out in which revisions a piece of code was changed then you can use a Mercurial command something like this:

hg grep --all PIECE_OF_CODE | awk 'BEGIN {FS=":"} {print $1" "$2}' | uniq

and you will get back a list of files with coresponding revisuin numbers:

repo/src/java/com/kovica/File1.java 30
repo/src/java/com/kovica/File1.java 10

Remove empty lines from a file on Linux using command line

This one is especially useful when searching through Glassfish's log files.
There are many ways you can remove empty lines from a file:

• awk 'NF' file
• sed '/^$/d' file
• grep "^$" -v file
• grep . file
• egrep "^[[:space:]]?$" -v file
• perl -n -e 'print unless /^\s*$/' file

And I'm sure there are many more. :)

Convert author in Mercurial repositiories

This is a summary of StackOverflow question http://stackoverflow.com/questions/12136895/change-the-author-in-mercurial-history


- cd repo1/.hg
- vi .hgrc and add
        [extensions]
        hgext.convert=
- cd $HOME
- vi authors.convert.list
        USER1 =USER2
- hg convert --authors $HOME/authors.convert.list repo1 repo1.NEW