It is interesting to use Vimperator in Firefox especially for Linux users. Simply, It saves time and speeds up our work.
To open all Bookmarks from a folder use the following command,
:bmarks! -folder folder_name
Likewise, To open all Bookmarks from other options like tag or keyword or title use the following commands,
:bmarks! -tag tag_name :bmarks! -keyword keyword_name :bmarks! -title title_name
Before that, if you want to add bookmaks using vimperator.
Goto the page and Use this command. Likewise for other options too.
:bmark -folder folder_name
Note: Vimperator Add-on must installed and enabled in your Browser.