#install rtl-433
sudo apt install rtl-433

#start rtl_433
#rtl_433 -Ga
rtl_433 -a 4

#press button on transmitter
#Binary output example: 00000001 01010101 11001100
#convert to decimal with bc
echo 'ibase=2;obase=A;000000010101010111000011'|bc

#in BASH with echo (does not work in zsh)
echo "$((2#000000010101010111000011))"

#output from example is 87491