PowerEdge and asset tag

Yeah, don't listen to these other guys. They clearly aren't reading or understanding your question. Since you want to script it, you'll want to use racadm. The command is going to look like this:

racadm>>get BIOS.MiscSettings

racadm get BIOS.MiscSettings
[Key=BIOS.Setup.1-1#MiscSettings]
AssetTag=
ErrPrompt=Disabled
ForceInt10=Disabled
NumLock=On

racadm>>set BIOS.MiscSettings.AssetTag 12345

racadm set BIOS.MiscSettings.AssetTag 12345
[Key=BIOS.Setup.1-1#MiscSettings]
RAC1017: Successfully modified the object value and the change is in
       pending state.
       To apply modified value, create a configuration job and reboot
       the system. To create the commit and reboot jobs, use "jobqueue"
       command. For more information about the "jobqueue" command, see RACADM
       help.

After that, you'll want to create a job like this:

racadm jobqueue create BIOS.Setup.1-1 -r none

And then reboot the machine since most BIOS changes require a reboot. Not sure if this one does or not. You should test this first, of course.

racadm serveraction powercycle

How you wrap your script will be up to your scripting skills, preferred language, or environment. I use python with pexpect to simulate an interactive session. I use a lot of regex and catch expected output from racadm. Beware that output may vary from generation to generation (e.g. iDRAC8 and iDRAC9 have different output strings).