# The `--link` command:

-L     partitions[:attributes]              Link partitions.
--link partitions[:attributes]

Linking partitions forces them to share not only the same model,
but the same parameters for that model.

Attributes that can be linked are `smodel`, `imodel`, and `scale`.
If no attributes are listed, then all three attributes are linked.

Partitions can be linked if the attribute is unspecified for all
partitions, as long as the default value or guessed value ends up
being the same for all of the linked partitions:

   bali-phy dna.fasta dna.fasta --link=1,2

Partitions cannot be linked if the attribute is specified for some
partitions, but not for others, or if the specified attributes differ.
Thus both of these commands will trigger an error:

   bali-phy dna.fasta dna.fasta --smodel=1:tn93 --link=1,2

   bali-phy dna.fasta dna.fasta --smodel=1:tn93 --smodel=1:hky85 --link=1,2

# Examples:

   bali-phy dna.fasta dna.fasta --smodel=1:tn93 --smodel=2:tn93 --link=1,2

   bali-phy dna.fasta amino-acids dna.fasta --link=1,3:smodel,scale
