According to this report, Tcl/Tk and Expect are used at the US DOD:

http://www.egovos.org/pdf/dodfoss.pdf

although they don't go into the specifics.

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Tcl 8.3 is blessed by DII COE [http://diicoe.disa.mil/coe/] as a COE Product. This effectively means, that if you need to be DII COE compliant, you can use Tcl. Perl is the only other scripting language listed.