Scripts take the form:
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PARTITIONS=ada0
DISTRIBUTIONS="kernel.txz base.txz ports.txz"
#!/bin/sh
echo "sshd_enable=YES" >> /etc/rc.conf
pkg add puppet
echo "System setup complete"
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The second part of the script (beginning with #!) is run in the newly
installed system after the installation onto ada0 (with default partitioning,
see scriptedpart for more complicated scenarios) is complete.