Four possible ways to do WHOIS in CO.PT service:

1 - Search in website whois.co.pt

2 - TXT Format: http://whois.co.pt/php/whoistxt.php?Dominio=dominio&TLD=tipo.
Example: http://whois.co.pt/php/whoistxt.php?Dominio=revenda&TLD=co.pt

3 - XML Format: http://whois.co.pt/php/whoisxml.php?Dominio=dominio&TLD=tipo.
Example: http://whois.co.pt/php/whoisxml.php?Dominio=revenda&TLD=co.pt

4 - Whois command: whois -h co.pt dominio.tipo
Example: whois -h co.pt revenda.co.pt

The expression dominio must be replaced by the domain name (ex:revenda) and tipo by co.pt or lda.pt.