1.Dd January 2, 2010 2.Dt SM-SCOPE 1 3.Os 4.Sh NAME 5.Nm Sm-scope 6.Nd scope of the spacing macro 7.Sh DESCRIPTION 8Using an abbreviated example from the 9.Xr ksh 1 10manual. 11.Pp 12Modifiers can be applied to the 13.Pf ${ Ns Ar name Ns } 14form of parameter substitution: 15.Bl -tag -width Ds 16.Sm off 17.It ${ Ar name No :- Ar word No } 18.Sm on 19If 20.Ar name 21is set and not 22.Dv NULL , 23it is substituted; otherwise, 24.Ar word 25is substituted. 26.El 27.Pp 28In the above modifiers, the 29.Ql \&: 30can be omitted, ... 31