shell command for "free nvram" and "free Ram"

Are there shell commands to get the free nvram and free ram ?

I don't know if it matters but the routers / firmwares are:
- AC68U with Shibby 136 K26ARM USB AIO-64K
- R7000 with Toastman v1.28.9008 Toastman-ARM K26ARM USB VPN-64K
- AC68U with Toastman v1.28.0510 MIPSR2Toastman-RT-AC K26AC USB VPN