.TH STRING 1 "June 14, 2017" OpenBSD
.SH NAME
string \- conditional testing whether a string is defined
.SH DESCRIPTION
.ie d mystr OOPS
.el mystr not yet defined
.br
.ds mystr mystrval
.ie d mystr now defined
.el OOPS
.if !d mystr OOPS
.PP
.ie d mymac OOPS
.el mymac not yet defined
.br
.de mymac
mymacval
..
.ie dmymac now defined
.el OOPS
.if !d  mymac OOPS
.PP
.ie d myren OOPS
.el myren not yet defined
.br
.rn SM myren
.ie d myren now defined
.el OOPS
.if !d myren OOPS