You cannot attack people in sleep mode. You cannot attack somebody who is less than 30% of your valuation.
Note that the 30% attack limit is only 5% if the target currently has a hostile mob heading towards, or is at, your company.
Special codes: */a/all = all units.
"h" = half total units. "t" third total units. "q" =
quarter total units. "f" = fifth total units.
Percentages can also be entered in the form "50%" etc. - this is percentage of units home, not total units.