it sounds like you might not have the appropriate PATH reference
add this to your .bashrc
export PATH=“~/.local/bin:$PATH”
export CARDANO_NODE_SOCKET_PATH=~/cardano-node/db/node.socket
export LD_LIBRARY_PATH=“/usr/local/lib:$LD_LIBRARY_PATH”
export PKG_CONFIG_PATH=“/usr/local/lib/pkgconfig:$PKG_CONFIG_PATH”
make sure the cardano-node/db/node.socket reference correctly points to your node.socket file
then then source .bashrc (just do this if the above is already in your .bashrc)
then try killall cardano-node