ESC-B(1)                    General Commands Manual                   ESC-B(1)

NNAAMMEE
     eesscc--BB - the roff escape B sequence: validate numerical expression

DDEESSCCRRIIPPTTIIOONN
     empty: 0
     digit: 1
     no number: 0
     trailing garbage: 0
     trailing operator: 0
     infix operator: 1
     infix and trailing operator: 0
     chain of operations: 1
     trailing para: 0
     unclosed para: 0
     empty pair of parentheses: 0
     parentheses containing number: 1
     complex expression: 1
     other delimiter: 1
     no closing delimiter: 0

OpenBSD                          July 4, 2017                          OpenBSD