How do I store the value of a Vim option into a Vim variable?
You can prefix the option name with the ‘&’ character and assign the option value to a Vim variable using the “let” command. For example, to store the value of the ‘textwidth’ option into the Vim variable “old_tw”, you can use the following command:
:let old_tw = &tw
To explicitly save buffer local options, use the prefix “l:”
:let old_tw = &l:tw
If you want to explicitly select the global option, use the “g:” prefix to the option name. To do the opposite, to set the ‘textwidth’ option with the value stored in the ‘old_tw’ variable, you can use the following command:
:let &tw = old_tw