CentOS Change Hostname

In order to see the hostname type uname -n and dnsdomainname to see

Perform the steps below as root or sudo

1. Change the HOSTNAME in /etc/sysconfig/network to desired new hostname
2. Change the hostname in /etc/hosts. (Add to the same line as localhost)
   
3. Source /etc/sysconfig/network
4. Type hostname $HOSTNAME
   
5. logout and log back in.
   

TIP: If you would like to strip off the domain name portion, which is stored elsewhere anyway.

• sed -i.bak 's/\.[a-z].*//g' /etc/sysconfig/network

Reference
http://www.how2centos.com/centos-change-the-hostname/

Reset MySQL root password

• Kill the mysql process using. Some process has may not be in the folder in the example below. The folder can be found my using ps aux | grep mysqld and looking for the file that ends with .pid or starts with mysqld
  
  • $: kill `cat /var/run/mysqld/mysqld.pid`
  
  


• Create a file with entries below.
  
  • UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root';
  
  
  • FLUSH PRIVILEGES;
  
  


• Start mysql using the command below. Where --init-file is the path to the file created above.
  
  • mysqld_safe --init-file=/home/me/mysql-init &
  
  
  
• Login to mysql using the new mysql root password
  

MySQL root password should be reset now.

Reference: http://dev.mysql.com/doc/refman/5.0/en/resetting-permissions.html#resetting-permissions-unix

Setup SVN on CentOS

http://wiki.centos.org/HowTos/Subversion

VMware: Increase disk space of Linux VM

Increase disk space to desired size using the VM Client.

Login to the VM and restart the machine (init 6)

After restart go to fdisk (fisk /dev/sda or /dev/hda etc.)

Create new partition using fdisk, save and exit.

If an LVM is used then the newly created partition will be needed to added the the LVM.

Follow instructions below. Assume new partition is /dev/sda3 (4GB), volume group is VolGroup-00 and Logical volume is LogVol-100

pvcreate /dev/sda3

vgextend VolGroup00 /dev/sda3

lvextend -L +4G /dev/mapper/VolGroup00-LogVol00

resize2fs /dev/mapper/VolGroup00-LogVol00

Set umask for a specific directory

Use the setfacl command. Examples below from man.

EXAMPLES

Granting an additional user read access

setfacl -m u:lisa:r file

Revoking write access from all groups and all named users (using the effective rights mask)

setfacl -m m::rx file

Removing a named group entry from a file’s ACL

setfacl -x g:staff file

Copying the ACL of one file to another

getfacl file1 | setfacl --set-file=- file2

Copying the access ACL into the Default ACL

getfacl --access dir | setfacl -d -M- dir

Found solution here

http://www.linuxforums.org/forum/slackware-linux/156119-solved-umask-specific-directory.html

Java File Upload with Servlet 3.0

Found it here

Recover GRUB menu after Ubuntu 9.10 update

A couple the GRUB menu got screwed up after an update. The recover process can be found here. But I had to take a couple additional steps to fix my GRUB.

1. Figure what your where your /boot and /root partition is installed in. My /boot was /dev/sdc2 and /root was /dev/sdc3.
2. Mount /root to /mnt using sudo mount /dev/sdc3 /mnt
3. Mount /boot to /mnt/boot using
   mount /dev/sdc2 /mnt/boot.
   NOTE: If both /root and /boot are on the same partition then you only have to mount the /root partition.
4. Check /mnt/boot/grub/device.map for an entry for /dev/sdc.
5. If /dev/sdc does not exist, then add it using vi. For example, the entries in mine were
   (hd0) /dev/sda
   (hd1) /dev/sdb
   So I added (hd2) /dev/sdc to list.
6. If this was not added to the list, the /root partition will not be found and the grub recovery will fail.
7. Next re-install the grub by executing
   sudo grub-install --root-directory=/mnt /dev/sdc
   
8. Reboot
9. Refresh the GRUB 2 menu by executing update-grub2