You can use the Ldifde.exe utility to export all directory objects to an .ldf file. The following command searches Houston OU and creates a file called exportdirectory.ldf containing those objects and its attributes:
Export Command ldifde -m -f c:\exportdirectory.ldf -d "OU=Houston,dc=Sivarajan,dc=Lab"
This command will export all the directory objects inside Houston OU to exportdirectory.ldf file.
The reason I used "-m" switch is, it will automatically strip all system-owned attributes when exporting the objects. If you don't use "-m" or filter using "-r" or "-o" option, you will get the following error message when you try to import the objects into Active Directory
"Unwilling to perform. The modification was not permitted for security reasons"
ldifde -i -f c:\exportdirectory.ldf
Also, you can use CSVDE command to import and export Active Directory objects.
Export Using CSVDE command
csvde -f c:\exportdirectory.csv -d "OU=Houston,dc=Sivarajan,dc=Lab"
Import Using CSVDE command
csvde -i -f c:\exportdirectory.csv