% read -p "My Msg: " Var
My Msg: my-val
% echo $Var
my google of:
bash prompt for input
% read --help
which seems to be a shell "builtin", since
% which read
says none in /bin...
Also I found: http://wiki.bash-hackers.org/commands/builtin/read
( also see: % man [or info] set [vs. env] )
I'm not sure about the "execute" part: maybe eval $Var vs. `cmd` or $(cmd)
(I googled: shell execute variable backquote)
Does this 'solve' your question? (I was surprised to see my XP cmd: set /? gave several pages!)
Feel free to ask more specific/details; best wishes!