a= rand(2,3); /// \sleftarrow{\normalfont \verb+2x3+ random matrix \verb+a+ is created}
typeof(a)    /// \sleftarrow{\begin{minipage}[t]{8cm}{\nf{}type of \verb+a+, \verb+constant+ stands {for} real or complex matrix} \end{minipage}}
a= [a, zeros(2,1)] /// \sleftarrow{\normalfont size of \verb+a+ dynamically increases}
a= 'scilab'; typeof(a) /// \sleftarrow{\normalfont redefining \verb+a+ through reassignment}
exists('a')  /// \sleftarrow{\normalfont checks {if} \verb+a+ exists }
clear('a'); exists('a')  /// \sleftarrow{\begin{minipage}[t]{6cm}{\nf{}removing \verb+a+ explicitly from current environment and verifying that \verb+a+ is gone }\end{minipage}}