I have set XSCHEM_SHAREDIR $env(HOME)/share/xschem in the xschemrc file at location ~/.xschem/xschem_library/xschem_sky130. But after invoking xschem by command $ xcshem -b & from the directory, when I write " echo $XSCHEM_SHAREDIR" on my terminal, it does not show any value. Am I using the correct way to check if the variable XSCHEM_SHAREDIR contains the value "~/share/xschem" or not ? Please clarify.