localhost bin # emerge net-misc/ipv6calc
Calculating dependencies \
!!! All ebuilds that could satisfy "net-misc/ipv6calc" have been masked.
!!! One of the following masked packages is required to complete your request:
- net-misc/ipv6calc-0.45 (masked by: missing keyword)
- net-misc/ipv6calc-0.51 (masked by: missing keyword)
- net-misc/ipv6calc-0.50 (masked by: missing keyword)
 
For more information, see MASKED PACKAGES section in the emerge man page or
refer to the Gentoo Handbook.
 
after adding
echo ">=net-misc/ipv6calc-0.51" >> /etc/portage/package.mask
and
localhost bin # emerge net-misc/ipv6calc
Calculating dependencies \
!!! All ebuilds that could satisfy "net-misc/ipv6calc" have been masked.
!!! One of the following masked packages is required to complete your request:
- net-misc/ipv6calc-0.45 (masked by: missing keyword)
- net-misc/ipv6calc-0.51 (masked by: package.mask, missing keyword)
- net-misc/ipv6calc-0.50 (masked by: missing keyword)
 
For more information, see MASKED PACKAGES section in the emerge man page or
refer to the Gentoo Handbook.
 
localhost bin # emerge =net-misc/ipv6calc
Calculating dependencies \
 
!!! '=net-misc/ipv6calc' is not a valid package atom.
!!! Please check ebuild(5) for full details.
!!! (Did you specify a version but forget to prefix with '='?)
localhost bin # emerge =net-misc/ipv6calc-0.51
Calculating dependencies \
!!! All ebuilds that could satisfy "=net-misc/ipv6calc-0.51" have been masked.
!!! One of the following masked packages is required to complete your request:
- net-misc/ipv6calc-0.51 (masked by: package.mask, missing keyword)
 
For more information, see MASKED PACKAGES section in the emerge man page or
refer to the Gentoo Handbook.
 
localhost bin #