Command line to only buy or sell at

[Mat]

Helllo World !
no it's not a web test

i feel strange, because i think  that my goal is super basic and curiously it appears to me super difficult !
i've been google plenty and i can't find an easy way to tell gekko by command line :   buy that binance pair at that value or sell it

Surely i missed the correct post or thread, but would be so great to find some help

Thank you neighbors