\documentclass[11pt]{article}

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\newcommand{\group}[1]{\bigskip\par\noindent\textbf{\large#1}\medskip}
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  #2\hfill\parbox[t]{3.4in}{\raggedright #3}\vskip 2pt}
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\newcommand{\superstar}{\raisebox{2pt}{*}}
\newcommand{\vbar}{$|$}

\begin{document}

%\twocolumn[\LARGE\centering{GBBopen REPL Commands Quick Reference Card}\vskip1cm]
\begin{center}
\LARGE GBBopen REPL Commands Quick Reference Card
\end{center}

\medskip

\group{Global commands}

\command{:commands}{\textrm{[}\var{system-name\/}\textrm{]}}%
  {Show extended-REPL commands\\(filtered by \var{system-name})}%
\command{:ds}{\var{object}}{Describe object}
\command{:exit}{}{Exit Lisp}
\command{:pa}{}{Show current package}%
\command{:pa}{\var{package-designator}}{Set current package}%
\command{:quit}{}{Exit Lisp}
\command{:systems}{}{Show all systems}%
\command{:undefine-system}{\var{system-name}}{Undefine a system}

\group{Module Manager commands}
\command{:cm}{\textrm{[}\var{module-name\/} 
              \textrm{[}\var{option\/}\superstar\textrm{]]}}%
  {Compile module (the last specified \var{module-name\/} and
    \var{options\/} are remembered as default values)}%
\command{:lm}{\textrm{[}\var{module-name\/} 
              \textrm{[}\var{option\/}\superstar\textrm{]]}}%
  {Load module (the last specified \var{module-name\/} and
    \var{options\/} are remembered as default values)}% 
\command{:lmf}{\textrm{[}\var{module-name file-name\/} 
               \textrm{[}\var{option\/}\superstar\textrm{]]}}%
  {Load module file (the last specified \var{module-name},
    \var{file-name}, and \var{options\/} are remembered 
    as default values)}%

\group{GBBopen Tools commands}
\command{:ot}{\var{offset-universal-time}}%
  {Describe offset-universal-time value}%
\command{:ut}{\var{universal-time}}{Describe universal-time value}%

\group{GBBopen commands}
\command{:di}{\parbox[t]{2.7in}{\var{instance\/} \vbar\\
   \{\var{instance-name\/}
   \textrm{[}\var{unit-classes-specifier\/}\textrm{]}\}}}%
  {Describe unit instance (sets \code{=})}%
\command{:dsbb}{}{Describe blackboard repository}%
\command{:dsi}{\parbox[t]{2.7in}{\var{instance\/} \vbar\\
   \{\var{instance-name\/}
   \textrm{[}\var{unit-classes-specifier\/}\textrm{]}\}}}%
  {Describe space instance (sets \code{=})}%
\command{:dsis}{\parbox[t]{2.7in}{\var{instance\/} \vbar\\
   \{\var{instance-name\/}
   \textrm{[}\var{unit-classes-specifier\/}\textrm{]}\}}}%
  {Describe space-instance storage (sets \code{=})}%
\command{:fi}{\var{instance-name\/}
   \textrm{[}\var{unit-classes-specifier\/}\textrm{]}}%
  {Find unit instance by name (sets \code{=})}%
\command{:fsi}{\parbox[t]{2.7in}{\var{instance\/} \vbar\\
   \{\var{instance-name\/}
   \textrm{[}\var{unit-classes-specifier\/}\textrm{]}\}}}%
  {Find space instance by path (sets \code{=})}%
\command{:pic}{\textrm{[}\var{unit-classes-specifier\/}\textrm{]}}%
  {Print instances of class}%

\end{document}