display the registers:
) info registers

display a variable value:
) print <variable>

display a value at every prompt:
) display <variable>

display program arguments:
) show args

display program threads:
) info threads

make a thread current:
) thread <#>

set a breakpoint:
) break <function>

remove a breakpoint:
) delete

single step:
) next

display the breakpoints:
) info break

disassemble code
) disas <function>

current frame:
) where