At first ,you have to download the last fixpack for DB2 v9.5 on:

http://www-01.ibm.com/support/docview.wss?rs=71&uid=swg24021563

Now, you are already to install your fixpack in DB2 V9.5, below you will see all steps necessary to install the fixpack with the installFixPack command:

A - Stop all applications connected on your databases, stop the instance, stop the DAS and stop fault monitors

db2 force applications all
db2stop
cd DB2DIR//das/bin$ ./db2admin stop
db2_kill
ps -ef | grep -i <instance_name>
#If there is any DB2 process
kill <PID of DB2 process>

B - Apply the fixpack with installFixPack command:

./installFixPack -b DB2DIR -f db2lib -f update

Example:

 ./installFixPack -f db2lib -f update -b /opt/ibm/db2/V9.5/

WHERE:

base-install-path:    Specifies the path where the DB2 product will be installed. Mandatory when -n is specified. The length of the path is limited to 128 characters and is a full path name.

    The –b option is not required for a non-root installation of DB2, but it is still mandatory for a root installation. If –b is used in a non-root install, the value of base-install-path must be the user’s HOME/sqllib directory, or else the path is considered invalid. If –b is not provided in a non-root install, the DB2 installer will use the user’s HOME/sqllib as the install path and continue. But, if –b is used and the provided install path has a DB2 copy installed by a root user, the path is considered invalid since the DB2 copy can only be updated by the user who installed it.

    Force option. -f with no argument is not supported. The force arguments below can be combined. For example, -f level -f db2lib.

    Force a down level or same level fix pack install. If the fix pack image is at a higher level than the installed DB2 product, this option is ignored.

    Force installFixPack to bypass the checking on DB2 library loading. To ensure that the instances or applications work properly after the installation, the DBM must be stopped for all the related instances (including all nodes for the related DPF instances), and all DB2 libraries related to the installation path must be unloaded.

    Force installFixPack to bypass all the checking on DB2 library loading, instance and DAS properly stopped or not. To ensure that the instances or applications work properly after the installation, the DBM must be stopped for all the related instances (including all nodes for the related DPF instances), and all DB2 libraries related to the installation path must be unloaded. If this option is specified, instance/DAS will not be updated. User needs to do the instance/DAS update manually after the installation. Also, note that the options update and install are mutually exclusive and cannot be specified in the same installation.

    Force installFixPack to bypass all the checking on DB2 library loading, instance and DAS properly stopped or not. To ensure that the instances or applications work properly after the installation, the DBM must be stopped for all the related instances (including all nodes for the related DPF instances), and all DB2 libraries related to the installation path must be unloaded. If this option is specified, instance/DAS will be updated. Also, note that the options update and install are mutually exclusive and cannot be specified in the same installation.

References: http://publib.boulder.ibm.com/infocenter/db2luw/v9r5/index.jsp