April 29, 2008
You get this message when you start Cygwin:
Your group is currently “mkpasswd”. This indicates that
the /etc/passwd (and possibly /etc/group) files should be rebuilt.
See the man pages for mkpasswd and mkgroup then, for example, run
mkpasswd -l [-d] > /etc/passwd
mkgroup -l [-d] > /etc/group
Note that the -d switch is necessary for domain users.
Issue the following commands to fix it:
mkpasswd -l -c > /etc/passwd
mkgroup -l -d > /etc/group
It will create a local user based on the current logged on user. The groups will be fetched from the domain. For the local installation the “-d” option can be omitted from mkgroup command.
Thanks to sinewalker for this tip.
April 27, 2008
Yesterday, I installed Ubuntu 8.04 to my second SATA II drive. I explicitly selected that grub be installed to second drive. After restarting, the computer failed to boot in both windows or linux and “GRUB” continued flooding on the screen. Here is how to solve this:
- Fix the XP boot record first: Boot with windows XP CD and when prompted press “R” to enter recovery console. Once in the console, enter:
to fix the master boot record of windows partition.
- Reboot the computer into windows and download the latest version of grub4dos. Do not be alarmed by the name, it is equally useful for XP NTFS partitions. Extract to a convenient location.
- In windows, go to Control Panel->System->Advanced->Startup and Recovery, click Settings
- In System Startup, click Edit
- Add the following line to the end of the opened (boot.ini) file:
and save the file.
grldrto the same location where boot.ini is located. It is usually found in C: drive and is a hidden and system file. You need to make it visible using appropriate folder view options.
- Download and install Ext2IFS for windows. Run the program and map ext3 based Ubuntu partition into windows.
- Copy menu.lst from /boot/grub from the Ubuntu partition to the same location as windows boot.ini file.
- Open menu.lst in wordpad and edit the following lines to your need:
title Ubuntu 8.04, kernel 2.6.24-16-genericIt was
hd0,0and I had to make it
hd1,0to refer to the second harddisk. This should boot Ubuntu fine, but you may want to make other changes in menu.lst file to your needs. Save and close menu.lst file.
- Now reboot your computer, press F8 at reboot to get to OS choice menu. Select
Start GRUB4DOS. Now you should see the usual grub menu. Select the first choice for Ubuntu and this should boot you in Ubuntu.
- If you are unable to get to grub menu after selecting
Start GRUB4DOSfrom the menu, please check again the location of
menu.lstfiles. You may try putting them in the C: root as well, if boot.ini location is different.
April 27, 2008
If you want to regularly backup your data from one location/hard-disk to another location/hard-disk on your windows-based computer, then SyncToy is very good candidate to accomplish this. It is a small utility from Microsoft in which you can easily create folder-pairs to synchronize. A number of actions, like merge, subscribe, echo, etc. are available that can be executed on a given pair.
The utility can be freely downloaded from here.
The desired sync operations can also be scheduled via Windows’ task scheduler. Simply look in the SyncToy help to find out.
April 24, 2008
If you receive this e-mail from your system, issuing the following command would fix the corrupted tables:
mysqlcheck --user=[username] --password=[pwd] --repair -A
April 21, 2008
apt-get install fail2ban
That’s all it takes to install this handy utility. It will monitor different services (ssh, postfix, courier, etc.) for repeated failed login attempts and will block the attacker for a given duration of time. All the settings can be found in
After you have updated the settings file, use:
to reload the new settings.
I was having brute-force dictionary attacks on
pop3 port, fail2ban blocked the attacker within 1 minute. Thanks to the developers.
April 21, 2008
mysql -uusername -pgets you into MySQL shell
show databases;shows all the databases;
show processes;shows all active users and queries as they happen
create database databasename;
creates a new database
grant all privileges on databasename.* to 'user'@'localhost' identified by 'password';
creates user with password with all privileges on given database
selects a database for further actions
displays the tables in the selected database
drop database databasename;
deletes all tables in databasename and deletes the database.
select * from mysql.user;
lists all the mysql users
drop user xxxx@localhost;
deletes the xxxx user from the localhost
mysqldump --all-databases -p | bzip2 -c > databasebackup.sql.bz2
dumps all mysql data in the compressed databasebackup.sql.bz2 file.
mysqldump -uroot -p databasename | bzip2 -c > databasename.sql.bz2
dumps databasename database in the compressed databasename.sql.bz2 file.