<s>
Portage	B-Application
is	O
a	O
package	B-Application
management	I-Application
system	I-Application
originally	O
created	O
for	O
and	O
used	O
by	O
Gentoo	B-Application
Linux	I-Application
and	O
also	O
by	O
ChromeOS	B-Operating_System
,	O
Calculate	B-Application
,	O
Sabayon	O
,	O
and	O
Funtoo	O
Linux	B-Application
among	O
others	O
.	O
</s>
<s>
Portage	B-Application
is	O
based	O
on	O
the	O
concept	O
of	O
ports	B-Application
collections	I-Application
.	O
</s>
<s>
Gentoo	B-Application
is	O
sometimes	O
referred	O
to	O
as	O
a	O
meta-distribution	O
due	O
to	O
the	O
extreme	O
flexibility	O
of	O
Portage	B-Application
,	O
which	O
makes	O
it	O
operating-system-independent	O
.	O
</s>
<s>
The	O
Gentoo/Alt	O
project	O
was	O
concerned	O
with	O
using	O
Portage	B-Application
to	O
manage	O
other	O
operating	B-General_Concept
systems	I-General_Concept
,	O
such	O
as	O
BSDs	B-Operating_System
,	O
macOS	B-Operating_System
and	O
Solaris	B-Application
.	O
</s>
<s>
The	O
most	O
notable	O
of	O
these	O
implementations	O
is	O
the	O
Gentoo/FreeBSD	O
project	O
.	O
</s>
<s>
There	O
is	O
an	O
ongoing	O
effort	O
called	O
the	O
Package	B-Application
Manager	I-Application
Specification	O
project	O
(	O
PMS	O
)	O
,	O
which	O
aims	O
to	O
standardise	O
and	O
document	O
the	O
behaviour	O
of	O
Portage	B-Application
,	O
allowing	O
the	O
ebuild	O
tree	B-Data_Structure
and	O
Gentoo	B-Application
system	O
packages	O
to	O
be	O
used	O
with	O
alternative	O
package	B-Application
managers	I-Application
such	O
as	O
Paludis	O
and	O
pkgcore	O
.	O
</s>
<s>
Its	O
goal	O
is	O
to	O
specify	O
the	O
exact	O
set	O
of	O
features	O
and	O
behaviour	O
of	O
package	B-Application
managers	I-Application
and	O
ebuilds	O
,	O
serving	O
as	O
an	O
authoritative	O
reference	O
for	O
Portage	B-Application
.	O
</s>
<s>
Portage	B-Application
is	O
similar	O
to	O
the	O
BSD-style	O
package	B-Application
management	I-Application
known	O
as	O
ports	B-Application
,	O
and	O
was	O
originally	O
designed	O
with	O
FreeBSD	B-Operating_System
's	O
ports	B-Application
in	O
mind	O
.	O
</s>
<s>
Portage	B-Application
is	O
written	O
in	O
the	O
Python	B-Language
programming	I-Language
language	I-Language
,	O
and	O
is	O
the	O
main	O
utility	O
that	O
defines	O
Gentoo	B-Application
.	O
</s>
<s>
Although	O
the	O
system	O
itself	O
is	O
known	O
as	O
Portage	B-Application
,	O
it	O
consists	O
of	O
two	O
main	O
parts	O
,	O
the	O
ebuild	O
system	O
and	O
emerge	O
.	O
</s>
<s>
The	O
ebuild	O
system	O
takes	O
care	O
of	O
the	O
actual	O
work	O
of	O
building	O
and	O
installing	O
packages	O
,	O
while	O
emerge	O
provides	O
an	O
interface	O
to	O
ebuild	O
:	O
managing	O
an	O
ebuild	O
repository	O
,	O
resolving	O
dependencies	B-Application
and	O
similar	O
issues	O
.	O
</s>
<s>
(	O
These	O
two	O
therefore	O
have	O
roughly	O
the	O
same	O
relation	O
as	O
rpm	B-Application
has	O
with	O
yum	B-Application
,	O
or	O
dpkg	B-Language
has	O
with	O
APT	B-Application
.	O
)	O
</s>
<s>
A	O
GTK+	B-Application
-based	O
GUI	O
,	O
Porthole	O
,	O
is	O
available	O
for	O
working	O
with	O
Portage	B-Application
.	O
</s>
<s>
Portage	B-Application
is	O
characterized	O
by	O
its	O
main	O
function	O
:	O
compiling	B-Language
from	O
source	O
code	O
the	O
packages	O
the	O
user	O
wishes	O
to	O
install	O
.	O
</s>
<s>
In	O
doing	O
so	O
it	O
allows	O
customization	O
of	O
compiler	B-Language
and	O
target-application	O
options	O
to	O
fit	O
the	O
system	O
's	O
specifications	O
and	O
the	O
user	O
's	O
own	O
wishes	O
.	O
</s>
<s>
Functionalities	O
related	O
to	O
system	O
management	O
include	O
:	O
allowing	O
parallel	O
package-version	O
installation	O
,	O
tracking	O
cross-package	O
dependencies	B-Application
,	O
managing	O
a	O
database	O
of	O
installed	O
packages	O
,	O
providing	O
a	O
local	O
ebuild	O
repository	O
,	O
and	O
synchronizing	O
of	O
the	O
local	O
Portage	B-Application
tree	B-Data_Structure
with	O
remote	O
repositories	O
.	O
</s>
<s>
Functionalities	O
related	O
to	O
individual	O
package	O
installation	O
include	O
:	O
specifying	O
compilation	B-Language
settings	O
for	O
the	O
target	O
machine	O
and	O
choosing	O
package	O
components	O
.	O
</s>
<s>
Portage	B-Application
distinguishes	O
between	O
three	O
levels	O
of	O
stability	O
in	O
ebuilds	O
:	O
stable	O
(	O
e.g.	O
,	O
the	O
software	O
works	O
as	O
intended	O
with	O
no	O
known	O
security	O
issues	O
at	O
time	O
of	O
release	O
)	O
,	O
keyword	O
masked	O
(	O
mainly	O
for	O
packages	O
that	O
have	O
not	O
been	O
sufficiently	O
tested	O
on	O
the	O
target	O
system	O
architecture	O
to	O
be	O
considered	O
stable	O
)	O
and	O
hard	O
masked	O
(	O
broken	O
or	O
very	O
insecure	O
)	O
packages	O
.	O
</s>
<s>
The	O
emerge	O
command-line	B-Application
tool	I-Application
is	O
the	O
heart	O
of	O
Portage	B-Application
.	O
</s>
<s>
The	O
emerge	O
tool	O
is	O
the	O
most	O
important	O
utility	O
for	O
accessing	O
the	O
features	O
of	O
Portage	B-Application
from	O
the	O
command	B-Application
line	I-Application
.	O
</s>
<s>
The	O
program	O
calculates	O
and	O
manages	O
dependencies	B-Application
,	O
executes	O
ebuilds	O
and	O
maintains	O
the	O
local	O
Portage	B-Application
tree	B-Data_Structure
and	O
database	O
of	O
installed	O
packages	O
.	O
</s>
<s>
The	O
compilation	B-Language
settings	O
used	O
by	O
ebuilds	O
can	O
be	O
changed	O
through	O
the	O
CFLAGS	B-Language
environment	O
variable	O
,	O
based	O
on	O
the	O
specifications	O
of	O
the	O
individual	O
computer	O
and	O
on	O
the	O
user	O
's	O
desire	O
for	O
optimization	O
.	O
</s>
<s>
What	O
emerge	O
installs	O
as	O
dependencies	B-Application
is	O
affected	O
by	O
the	O
USE	O
flag-settings	O
.	O
</s>
<s>
The	O
Portage	B-Application
system	O
offers	O
the	O
use	O
of	O
"	O
USE	O
flags	O
"	O
,	O
which	O
allows	O
users	O
to	O
indicate	O
which	O
software	O
features	O
they	O
would	O
like	O
to	O
include	O
(	O
and	O
exclude	O
)	O
while	O
building	O
packages	O
.	O
</s>
<s>
For	O
example	O
,	O
there	O
is	O
a	O
USE	O
flag	O
to	O
include	O
DVD	O
support	O
,	O
where	O
available	O
,	O
in	O
packages	O
compiled	B-Language
with	O
the	O
flag	O
enabled	O
.	O
</s>
<s>
The	O
USE	O
flags	O
affect	O
which	O
dependencies	B-Application
are	O
required	O
,	O
generally	O
affecting	O
which	O
optional	O
features	O
will	O
be	O
built	O
into	O
a	O
given	O
program	O
when	O
it	O
is	O
compiled	B-Language
.	O
</s>
<s>
For	O
example	O
,	O
in	O
packages	O
which	O
use	O
a	O
configure	B-Device
script	I-Device
,	O
the	O
USE	O
flag	O
feature	O
would	O
translate	O
to	O
./configure	O
--with-feature	O
.	O
</s>
<s>
The	O
specification	O
of	O
USE	O
flags	O
is	O
the	O
usual	O
way	O
to	O
configure	B-Device
programs	O
on	O
Gentoo	B-Application
.	O
</s>
<s>
A	O
list	O
of	O
available	O
USE	O
flags	O
is	O
available	O
at	O
the	O
Gentoo	B-Application
website	O
's	O
.	O
</s>
<s>
Gentoo	B-Application
does	O
not	O
,	O
by	O
default	O
,	O
use	O
binary	O
packages	O
as	O
other	O
package	B-Application
management	I-Application
systems	I-Application
do	O
(	O
like	O
pacman	O
or	O
apt	B-Application
)	O
,	O
employing	O
instead	O
a	O
format	O
known	O
as	O
the	O
ebuild	O
.	O
</s>
<s>
Whereas	O
RPM	B-Application
binaries	O
are	O
precompiled	O
binaries	O
,	O
ebuilds	O
are	O
shell	B-Language
scripts	I-Language
with	O
variables	O
and	O
functions	O
which	O
contain	O
a	O
description	O
of	O
the	O
software	O
,	O
and	O
instructions	O
on	O
how	O
to	O
obtain	O
,	O
configure	B-Device
,	O
compile	B-Language
,	O
and	O
install	O
it	O
,	O
more	O
closely	O
akin	O
to	O
(	O
but	O
more	O
powerful	O
than	O
)	O
the	O
.spec	O
files	O
distributed	O
in	O
SRPMs	O
.	O
</s>
<s>
The	O
official	O
repository	O
provides	O
over	O
19,600	O
ebuilds	O
,	O
the	O
majority	O
of	O
which	O
are	O
distributed	O
by	O
the	O
Gentoo	B-Application
mirrors	O
.	O
</s>
<s>
Historically	O
,	O
Gentoo	B-Application
has	O
provided	O
pre-compiled	O
binary	O
packages	O
for	O
many	O
common	O
programs	O
,	O
especially	O
those	O
which	O
are	O
lengthy	O
to	O
compile	B-Language
,	O
such	O
as	O
Mozilla	B-Application
Firefox	I-Application
and	O
OpenOffice.org	B-Application
.	O
</s>
<s>
Example	O
of	O
ebuild	O
for	O
GNOME	B-Language
Terminator	I-Language
:	O
</s>
<s>
Gentoo	B-Application
does	O
have	O
a	O
binary	O
packaging	O
format	O
,	O
which	O
is	O
a	O
.tbz2	O
file	O
(	O
tar	B-Application
with	O
bzip2	B-Application
compression	O
)	O
with	O
additional	O
metadata	O
.	O
</s>
<s>
This	O
feature	O
enables	O
the	O
building	O
of	O
binary	O
packages	O
on	O
one	O
system	O
(	O
using	O
Portage	B-Application
's	O
buildpkg	O
or	O
quickpkg	O
)	O
followed	O
by	O
quick	O
installation	O
on	O
compatible	O
systems	O
(	O
with	O
Portage	B-Application
's	O
getbinpkg	O
or	O
emerge	O
-K	O
)	O
.	O
</s>
<s>
Masking	O
is	O
how	O
Gentoo	B-Application
determines	O
which	O
packages	O
are	O
suitable	O
for	O
a	O
system	O
.	O
</s>
<s>
they	O
are	O
available	O
for	O
systems	O
with	O
an	O
ACCEPT_KEYWORDS	O
make.conf	O
entry	O
starting	O
with	O
the	O
character	O
~	O
,	O
such	O
as	O
~	O
x86	B-Operating_System
,	O
~	O
amd64	B-Device
,	O
~	O
ppc	O
)	O
.	O
</s>
<s>
An	O
individual	O
keyword	O
masked	O
package	O
can	O
be	O
unmasked	O
by	O
adding	O
a	O
line	O
with	O
the	O
full	O
package	O
name	O
and	O
keyword	O
to	O
some	O
file	O
within	O
the	O
/etc/portage/package.accept_keywords/	O
directory	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
a	O
masked	O
package	O
had	O
multiple	O
masked	O
dependencies	B-Application
,	O
the	O
user	O
could	O
make	O
a	O
directory	O
with	O
the	O
name	O
of	O
the	O
original	O
masked	O
package	O
,	O
and	O
put	O
all	O
the	O
mask	O
files	O
for	O
the	O
package	O
and	O
its	O
dependencies	B-Application
in	O
that	O
directory	O
.	O
</s>
<s>
This	O
scheme	O
replaces	O
the	O
older	O
scheme	O
of	O
having	O
/etc/portage/package.accept_keywords	O
as	O
one	O
text	O
file	O
.	O
</s>
<s>
Packages	O
with	O
known	O
problems	O
or	O
not	O
considered	O
mature	O
enough	O
to	O
be	O
candidates	O
for	O
stable	O
are	O
hard	O
masked	O
by	O
one	O
of	O
the	O
various	O
package.mask	O
files	O
in	O
/usr/portage/profiles	O
,	O
and	O
such	O
entries	O
are	O
generally	O
accompanied	O
by	O
a	O
comment	O
from	O
developers	O
explaining	O
the	O
reason	O
for	O
the	O
mask	O
.	O
</s>
<s>
Gentoo/Alt	O
is	O
a	O
project	O
created	O
to	O
manage	O
porting	O
the	O
portage	B-Application
framework	O
and	O
other	O
features	O
to	O
other	O
operating	B-General_Concept
systems	I-General_Concept
,	O
such	O
as	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
and	O
the	O
free	B-Operating_System
BSDs	I-Operating_System
.	O
</s>
<s>
Gentoo/Alt	O
was	O
set	O
up	O
by	O
Pieter	O
Van	O
den	O
Abeele	O
and	O
Daniel	O
Robbins	O
after	O
Pieter	O
Van	O
den	O
Abeele	O
founded	O
Gentoo	B-Application
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
.	O
</s>
<s>
Gentoo	B-Application
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
was	O
the	O
first	O
non-Linux	O
project	O
of	O
Gentoo	B-Application
and	O
focused	O
on	O
making	O
the	O
Gentoo	B-Application
experience	O
available	O
on	O
Apple	O
's	O
operating	B-General_Concept
system	I-General_Concept
by	O
introducing	O
the	O
Portage	B-Application
system	O
as	O
a	O
separate	O
entity	O
.	O
</s>
<s>
This	O
was	O
roughly	O
similar	O
to	O
Fink	B-Application
and	O
MacPorts	B-Application
,	O
but	O
it	O
used	O
Portage	B-Application
instead	O
of	O
a	O
Debian-like	O
or	O
Ports-like	O
system	O
.	O
</s>
<s>
Later	O
on	O
,	O
Gentoo	B-Application
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
was	O
made	O
a	O
subproject	O
of	O
Gentoo/Alt	O
.	O
</s>
<s>
Gentoo	B-Application
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
has	O
been	O
superseded	O
by	O
Gentoo	B-Application
Prefix	O
,	O
which	O
is	O
currently	O
what	O
Gentoo	B-Application
offers	O
to	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
users	O
.	O
</s>
<s>
The	O
Prefix	O
project	O
on	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
is	O
tested	O
and	O
supported	O
on	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
Tiger	O
,	O
Leopard	O
and	O
Snow	O
Leopard	O
on	O
PowerPC	B-Architecture
,	O
IA-32	B-Device
,	O
and	O
x86-64	B-Device
architectures	O
.	O
</s>
<s>
Gentoo/FreeBSD	O
brings	O
the	O
Gentoo	B-Application
Linux	I-Application
design	O
,	O
structure	O
,	O
and	O
tools	O
such	O
as	O
Portage	B-Application
and	O
the	O
Gentoo	B-Application
Linux	I-Application
base	O
layout	O
to	O
the	O
FreeBSD	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Gentoo	B-Application
's	O
GNU	B-Application
toolchain	I-Application
is	O
used	O
instead	O
of	O
the	O
original	O
FreeBSD	B-Operating_System
one	O
.	O
</s>
<s>
Although	O
the	O
project	O
is	O
no	O
longer	O
maintained	O
by	O
any	O
active	O
Gentoo	B-Application
developers	O
,	O
there	O
are	O
instructions	O
that	O
allow	O
installation	O
of	O
a	O
full	O
Gentoo/FreeBSD	O
system	O
.	O
</s>
<s>
FreeBSD	B-Operating_System
system	O
ebuilds	O
are	O
integrated	O
into	O
the	O
main	O
portage	B-Application
tree	B-Data_Structure
,	O
but	O
this	O
port	O
is	O
far	O
from	O
being	O
complete	O
due	O
to	O
the	O
amount	O
of	O
packages	O
needing	O
to	O
be	O
ported	O
and	O
the	O
lack	O
of	O
a	O
proper	O
Live	O
CD	O
(	O
FreeSBIE	B-Application
's	O
Live	O
CD	O
or	O
FreeBSD	B-Operating_System
setup	O
CD	O
is	O
used	O
during	O
installation	O
)	O
.	O
</s>
<s>
The	O
current	O
(	O
semi	O
)	O
official	O
logo	O
for	O
Gentoo/FreeBSD	O
is	O
a	O
daemonized	O
"	O
g	O
"	O
,	O
derived	O
from	O
original	O
Gentoo	B-Application
Linux	I-Application
logo	O
and	O
inspired	O
by	O
the	O
BSD	B-Operating_System
Daemon	O
.	O
</s>
<s>
Gentoo/NetBSD	O
is	O
a	O
project	O
to	O
provide	O
a	O
GNU	B-Operating_System
userland	O
managed	O
by	O
Portage	B-Application
with	O
a	O
NetBSD	O
kernel	O
.	O
</s>
<s>
Only	O
the	O
x86	B-Operating_System
architecture	I-Operating_System
is	O
targeted	O
and	O
the	O
system	O
as	O
a	O
whole	O
is	O
in	O
an	O
incomplete	O
state	O
.	O
</s>
<s>
Gentoo/OpenBSD	O
is	O
a	O
Gentoo/	O
*BSD	O
subproject	O
to	O
port	O
Gentoo	B-Application
features	O
such	O
as	O
Portage	B-Application
to	O
the	O
OpenBSD	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
An	O
ISO	B-General_Concept
image	I-General_Concept
based	O
on	O
OpenBSD	B-Operating_System
3.8	O
is	O
currently	O
maintained	O
by	O
Karol	O
Pasternak	O
and	O
can	O
be	O
downloaded	O
from	O
the	O
project	O
's	O
web	O
site	O
.	O
</s>
<s>
Gentoo/DragonFlyBSD	O
is	O
a	O
currently	O
unofficial	O
port	O
to	O
the	O
DragonFlyBSD	B-Application
kernel	O
.	O
</s>
<s>
An	O
unofficial	O
port	O
to	O
GNU	B-Application
Hurd	I-Application
was	O
also	O
being	O
developed	O
,	O
but	O
was	O
abandoned	O
in	O
late	O
2006	O
.	O
</s>
<s>
Led	O
by	O
Benda	O
Xu	O
,	O
"	O
Gentoo	B-Application
RAP	O
for	O
Android	B-Application
Devices	O
"	O
installs	O
a	O
variant	O
of	O
Gentoo	B-Application
called	O
Gentoo	B-Application
RAP	O
in	O
a	O
directory	O
prefix	O
alongside	O
Android	B-Application
.	O
</s>
<s>
The	O
Linux	B-Application
kernel	O
is	O
used	O
by	O
both	O
Android	B-Application
and	O
Gentoo	B-Application
RAP	O
.	O
</s>
<s>
Gentoo/Interix	O
(	O
eprefix	O
)	O
is	O
a	O
port	O
of	O
Gentoo	B-Application
that	O
runs	O
atop	O
the	O
Interix	B-Operating_System
Subsystem	O
for	O
Windows	O
which	O
is	O
also	O
known	O
as	O
Microsoft	O
Windows	O
Services	O
for	O
UNIX	O
(	O
SFU	O
)	O
or	O
Subsystem	B-Operating_System
for	I-Operating_System
Unix-based	I-Operating_System
Applications	I-Operating_System
(	O
SUA	O
)	O
.	O
</s>
<s>
A	O
result	O
of	O
the	O
Gentoo/Interix	O
project	O
is	O
the	O
ability	O
to	O
install	O
and	O
use	O
the	O
Portage	B-Application
system	O
to	O
emerge	O
native	O
Windows	O
applications	O
(	O
requires	O
Visual	O
Studio	O
,	O
2008	O
Express	O
Edition	O
will	O
do	O
too	O
)	O
.	O
</s>
<s>
However	O
,	O
this	O
feature	O
does	O
not	O
support	O
the	O
wide	O
variety	O
of	O
packages	O
supported	O
by	O
other	O
platforms	O
(	O
including	O
Interix	B-Operating_System
)	O
.	O
</s>
<s>
An	O
unofficial	O
port	O
to	O
the	O
Solaris	B-Application
operating	I-Application
system	I-Application
,	O
"	O
Portaris	O
"	O
,	O
was	O
announced	O
around	O
2006	O
,	O
but	O
never	O
got	O
into	O
a	O
public	O
state	O
.	O
</s>
<s>
It	O
was	O
superseded	O
by	O
the	O
Gentoo	B-Application
Prefix	O
project	O
.	O
</s>
<s>
Started	O
in	O
2011	O
as	O
a	O
Google	B-Application
Summer	I-Application
of	I-Application
Code	I-Application
project	O
,	O
Plan	B-Operating_System
9	I-Operating_System
For	O
Gentoo	B-Application
takes	O
the	O
Gentoo	B-Application
base	O
and	O
overlays	O
a	O
userspace	B-Operating_System
inspired	O
by	O
Plan	B-Operating_System
9	I-Operating_System
.	O
</s>
<s>
The	O
stated	O
objectives	O
of	O
the	O
project	O
are	O
to	O
have	O
better	O
hardware	B-Architecture
support	O
,	O
better	O
software	O
support	O
and	O
to	O
create	O
a	O
"	O
culture	O
shock	O
"	O
for	O
people	O
that	O
have	O
previously	O
used	O
Linux	B-Application
systems	O
.	O
</s>
