transient information about idiosyncrasies of some of the ports, almost
all of which are in a state of constant evolution. Thus, this material
should be considered a perpetual work in progress
-(<IMG SRC="yellow_sign.gif" ALT="Under Construction">).
+(C<< <IMG SRC="yellow_sign.gif" ALT="Under Construction"> >>).
=head1 ISSUES
Some of this may be confusing. Here's a handy reference to the ASCII CR
and LF characters. You can print it out and stick it in your wallet.
- LF == \012 == \x0A == \cJ == ASCII 10
- CR == \015 == \x0D == \cM == ASCII 13
+ LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
+ CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
| Unix | DOS | Mac |
---------------------------
"\n", and "\n" on output becomes CRLF.
These are just the most common definitions of C<\n> and C<\r> in Perl.
-There may well be others.
+There may well be others. For example, on an EBCDIC implementation such
+as z/OS or OS/400 the above material is similar to "Unix" but the code
+numbers change:
+
+ LF eq \025 eq \x15 eq chr(21) eq CP-1047 21
+ LF eq \045 eq \x25 eq \cU eq chr(37) eq CP-0037 37
+ CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
+ CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
+
+ | z/OS | OS/400 |
+ ----------------------
+ \n | LF | LF |
+ \r | CR | CR |
+ \n * | LF | LF |
+ \r * | CR | CR |
+ ----------------------
+ * text-mode STDIO
=head2 Numbers endianness and Width
the standard distribution as of Perl 5.005) and Storable (included as
of perl 5.8). Keeping all data as text significantly simplifies matters.
+The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
+how far EBCDIC, or more precisely UTF-EBCDIC will go.
+
=head2 Files and Filesystems
Most platforms these days structure files in a hierarchical fashion.
modification timestamp), or one second granularity of any timestamps
(e.g. the FAT filesystem limits the time granularity to two seconds).
+The "inode change timestamp" (the C<-C> filetest) may really be the
+"creation timestamp" (which it is not in UNIX).
+
VOS perl can emulate Unix filenames with C</> as path separator. The
native pathname characters greater-than, less-than, number-sign, and
percent-sign are always accepted.
separator, or go native and use C<.> for path separator and C<:> to
signal filesystems and disk names.
+Don't assume UNIX filesystem access semantics: that read, write,
+and execute are all the permissions there are, and even if they exist,
+that their semantics (for example what do r, w, and x mean on
+a directory) are the UNIX ones. The various UNIX/POSIX compatibility
+layers usually try to make interfaces like chmod() work, but sometimes
+there simply is no good mapping.
+
If all this is intimidating, have no (well, maybe only a little)
fear. There are modules that can help. The File::Spec modules
provide methods to do the Right Thing on whatever platform happens
Don't assume a text file will end with a newline. They should,
but people forget.
-Do not have two files of the same name with different case, like
-F<test.pl> and F<Test.pl>, as many platforms have case-insensitive
-filenames. Also, try not to have non-word characters (except for C<.>)
-in the names, and keep them to the 8.3 convention, for maximum
-portability, onerous a burden though this may appear.
+Do not have two files or directories of the same name with different
+case, like F<test.pl> and F<Test.pl>, as many platforms have
+case-insensitive (or at least case-forgiving) filenames. Also, try
+not to have non-word characters (except for C<.>) in the names, and
+keep them to the 8.3 convention, for maximum portability, onerous a
+burden though this may appear.
Likewise, when using the AutoSplit module, try to keep your functions to
8.3 naming and case-insensitive conventions; or, at the least,
make it so the resulting files have a unique (case-insensitively)
first 8 characters.
-Whitespace in filenames is tolerated on most systems, but not all.
+Whitespace in filenames is tolerated on most systems, but not all,
+and even on systems where it might be tolerated, some utilities
+might become confused by such whitespace.
+
Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
Don't assume C<< > >> won't be the first character of a filename.
-Always use C<< < >> explicitly to open a file for reading,
-unless you want the user to be able to specify a pipe open.
+Always use C<< < >> explicitly to open a file for reading, or even
+better, use the three-arg version of open, unless you want the user to
+be able to specify a pipe open.
- open(FILE, "< $existing_file") or die $!;
+ open(FILE, '<', $existing_file) or die $!;
If filenames might use strange characters, it is safest to open it
with C<sysopen> instead of C<open>. C<open> is magic and can
translate characters like C<< > >>, C<< < >>, and C<|>, which may
be the wrong thing to do. (Sometimes, though, it's the right thing.)
+Three-arg open can also help protect against this translation in cases
+where it is undesirable.
+
+Don't use C<:> as a part of a filename since many systems use that for
+their own semantics (MacOS Classic for separating pathname components,
+many networking schemes and utilities for separating the nodename and
+the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
+C<|>.
+
+Don't assume that in pathnames you can collapse two leading slashes
+C<//> into one: some networking and clustering filesystems have special
+semantics for that. Let the operating system to sort it out.
+
+The I<portable filename characters> as defined by ANSI C are
+
+ a b c d e f g h i j k l m n o p q r t u v w x y z
+ A B C D E F G H I J K L M N O P Q R T U V W X Y Z
+ 0 1 2 3 4 5 6 7 8 9
+ . _ -
+
+and the "-" shouldn't be the first character. If you want to be
+hypercorrect, stay case-insensitive and within the 8.3 naming
+convention (all the files and directories have to be unique within one
+directory if their names are lowercased and truncated to eight
+characters before the C<.>, if any, and to three characters after the
+C<.>, if any). (And do not use C<.>s in directory names.)
=head2 System Interaction
Don't count on specific values of C<$!>.
+=head2 Command names versus file pathnames
+
+Don't assume that the name used to invoke a command or program with
+C<system> or C<exec> can also be used to test for the existence of the
+file that holds the executable code for that command or program.
+First, many systems have "internal" commands that are built-in to the
+shell or OS and while these commands can be invoked, there is no
+corresponding file. Second, some operating systems (e.g., Cygwin,
+DJGPP, OS/2, and VOS) have required suffixes for executable files;
+these suffixes are generally permitted on the command name but are not
+required. Thus, a command like "perl" might exist in a file named
+"perl", "perl.exe", or "perl.pm", depending on the operating system.
+The variable "_exe" in the Config module holds the executable suffix,
+if any. Third, the VMS port carefully sets up $^X and
+$Config{perlpath} so that no further processing is required. This is
+just as well, because the matching regular expression used below would
+then have to deal with a possible trailing version number in the VMS
+file name.
+
+To convert $^X to a file pathname, taking account of the requirements
+of the various operating system possibilities, say:
+ use Config;
+ $thisperl = $^X;
+ if ($^O ne 'VMS')
+ {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
+
+To convert $Config{perlpath} to a file pathname, say:
+ use Config;
+ $thisperl = $Config{perlpath};
+ if ($^O ne 'VMS')
+ {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
+
=head2 Interprocess Communication (IPC)
In general, don't directly access the system in code meant to be
=head2 Character sets and character encoding
-Assume little about character sets. Assume nothing about
-numerical values (C<ord>, C<chr>) of characters. Do not
-assume that the alphabetic characters are encoded contiguously (in
-the numeric sense). Do not assume anything about the ordering of the
-characters. The lowercase letters may come before or after the
-uppercase letters; the lowercase and uppercase may be interlaced so
-that both `a' and `A' come before `b'; the accented and other
-international characters may be interlaced so that E<auml> comes
-before `b'.
+Assume very little about character sets.
+
+Assume nothing about numerical values (C<ord>, C<chr>) of characters.
+Do not use explicit code point ranges (like \xHH-\xHH); use for
+example symbolic character classes like C<[:print:]>.
+
+Do not assume that the alphabetic characters are encoded contiguously
+(in the numeric sense). There may be gaps.
+
+Do not assume anything about the ordering of the characters.
+The lowercase letters may come before or after the uppercase letters;
+the lowercase and uppercase may be interlaced so that both `a' and `A'
+come before `b'; the accented and other international characters may
+be interlaced so that E<auml> comes before `b'.
=head2 Internationalisation
Most multi-user platforms provide basic levels of security, usually
implemented at the filesystem level. Some, however, do
-not--unfortunately. Thus the notion of user id, or "home" directory,
+not-- unfortunately. Thus the notion of user id, or "home" directory,
or even the state of being logged-in, may be unrecognizable on many
platforms. If you write programs that are security-conscious, it
is usually best to know what type of system you will be running
under so that you can write code explicitly for that platform (or
class of platforms).
+Don't assume the UNIX filesystem access semantics: the operating
+system or the filesystem may be using some ACL systems, which are
+richer languages than the usual rwx. Even if the rwx exist,
+their semantics might be different.
+
+(From security viewpoint testing for permissions before attempting to
+do something is silly anyway: if one tries this, there is potential
+for race conditions-- someone or something might change the
+permissions between the permissions check and the actual operation.
+Just try the operation.)
+
+Don't assume the UNIX user and group semantics: especially, don't
+expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
+for switching identities (or memberships).
+
+Don't assume set-uid and set-gid semantics. (And even if you do,
+think twice: set-uid and set-gid are a known can of security worms.)
+
=head2 Style
For those times when it is necessary to have platform-specific code,
programs to aid in the testing, or when (as noted above) the tests
assume certain things about the filesystem and paths. Be careful
not to depend on a specific output style for errors, such as when
-checking C<$!> after an system call. Some platforms expect a certain
+checking C<$!> after a system call. Some platforms expect a certain
output format, and perl on those platforms may have been adjusted
accordingly. Most specifically, don't anchor a regex when testing
an error value.
--------------------------------------------
AIX aix aix
BSD/OS bsdos i386-bsdos
+ Darwin darwin darwin
dgux dgux AViiON-dgux
DYNIX/ptx dynixptx i386-dynixptx
FreeBSD freebsd freebsd-i386
The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
-ftp://hobbes.nmsu.edu/pub/os2/dev/emx. Also L<perlos2>.
+ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
=item *
(installed as L<perlvos>). Perl on VOS can accept either VOS- or
Unix-style file specifications as in either of the following:
- $ perl -ne "print if /perl_setup/i" >system>notices
- $ perl -ne "print if /perl_setup/i" /system/notices
+ C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
+ C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
or even a mixture of both as in:
- $ perl -ne "print if /perl_setup/i" >system/notices
+ C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
Even though VOS allows the slash character to appear in object
names, because the VOS port of Perl interprets it as a pathname
renamed before they can be processed by Perl. Note that VOS limits
file names to 32 or fewer characters.
-See F<README.vos> for restrictions that apply when Perl is built
-with the alpha version of VOS POSIX.1 support.
-
-Perl on VOS is built without any extensions and does not support
-dynamic loading.
+Perl on VOS can be built using two different compilers and two different
+versions of the POSIX runtime. The recommended method for building full
+Perl is with the GNU C compiler and the generally-available version of
+VOS POSIX support. See F<README.vos> (installed as L<perlvos>) for
+restrictions that apply when Perl is built using the VOS Standard C
+compiler or the alpha version of VOS POSIX support.
The value of C<$^O> on VOS is "VOS". To determine the architecture that
you are running on without resorting to loading all of C<%Config> you
=item *
-F<README.vos>
+F<README.vos> (installed as L<perlvos>)
=item *
There is no specific mailing list for Perl on VOS. You can post
comments to the comp.sys.stratus newsgroup, or subscribe to the general
-Stratus mailing list. Send a letter with "Subscribe Info-Stratus" in
+Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
the message body to majordomo@list.stratagy.com.
=item *
-VOS Perl on the web at http://ftp.stratus.com/pub/vos/vos.html
+VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
=back
OS $^O $Config{'archname'}
------------------------------------------
Amiga DOS amigaos m68k-amigos
+ BeOS beos
MPE/iX mpeix PA-RISC1.1
See also:
Access permissions are mapped onto VOS access-control list changes. (VOS)
+The actual permissions set depend on the value of the C<CYGWIN>
+in the SYSTEM environment settings. (Cygwin)
+
=item chown LIST
Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>, VOS)
Does not automatically flush output handles on some platforms.
(SunOS, Solaris, HP-UX)
+=item exit EXPR
+
+=item exit
+
+Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
+mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
+with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
+function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
+(C<1>); this mapping cannot be overridden. Any other argument to exit()
+is used directly as Perl's exit status. (VMS)
+
=item fcntl FILEHANDLE,FUNCTION,SCALAR
Not implemented. (Win32, VMS)
Not implemented. (Win32, Plan9)
-=item setpwent
-
-Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
-
-=item setgrent
-
-Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
-
=item sethostent STAYOPEN
Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
Not implemented. (Plan9, Win32)
-=item exit EXPR
-
-=item exit
-
-Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
-mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
-with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
-function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
-(C<1>); this mapping cannot be overridden. Any other argument to exit()
-is used directly as Perl's exit status. (VMS)
-
=item getsockopt SOCKET,LEVEL,OPTNAME
Not implemented. (Plan9)
=item select RBITS,WBITS,EBITS,TIMEOUT
-Only implemented on sockets. (Win32)
+Only implemented on sockets. (Win32, VMS)
Only reliable on sockets. (S<RISC OS>)
-Note that the C<socket FILEHANDLE> form is generally portable.
+Note that the C<select FILEHANDLE> form is generally portable.
=item semctl ID,SEMNUM,CMD,ARG
=item setgrent
-Not implemented. (MPE/iX, Win32)
+Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, VMS, S<RISC OS>)
=item setpgrp PID,PGRP
=item setpwent
-Not implemented. (MPE/iX, Win32)
+Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>)
=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
'not numeric' warnings.
mtime and atime are the same thing, and ctime is creation time instead of
-inode change time. (S<Mac OS>)
+inode change time. (S<Mac OS>).
+
+ctime not supported on UFS (S<Mac OS X>).
+
+ctime is creation time instead of inode change time (Win32).
device and inode are not meaningful. (Win32)
=item system LIST
+In general, do not assume the UNIX/POSIX semantics that you can shift
+C<$?> right by eight to get the exit value, or that C<$? & 127>
+would give you the number of the signal that terminated the program,
+or that C<$? & 128> would test true if the program was terminated by a
+coredump. Instead, use the POSIX W*() interfaces: for example, use
+WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
+value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
+signal. Core dumping is not a portable concept, so there's no portable
+way to test for that.
+
Only implemented if ToolServer is installed. (S<Mac OS>)
As an optimization, may not call the command shell specified in
=item utime LIST
-Only the modification time is updated. (S<Mac OS>, VMS, S<RISC OS>)
+Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
May not behave as expected. Behavior depends on the C runtime
library's implementation of utime(), and the filesystem being
=head1 Supported Platforms
-As of early 2001 (the Perl releases 5.6.1 and 5.7.1), the following
-platforms are able to build Perl from the standard source code
-distribution available at http://www.perl.com/CPAN/src/index.html
-
- AIX
- AmigaOS
- Darwin (Mac OS X)
- DG/UX
- DOS DJGPP 1)
- DYNIX/ptx
- EPOC
- FreeBSD
- HP-UX
- IRIX
- Linux
- MachTen
- MacOS Classic 2)
- NonStop-UX
- ReliantUNIX (SINIX)
- OpenBSD
- OpenVMS (VMS)
- OS/2
- OS X
- QNX
- Solaris
- Tru64 UNIX (DEC OSF/1, Digital UNIX)
- UNICOS
- UNICOS/mk
- VOS
- Win32/NT/2K 3)
+As of June 2002 (the Perl release 5.8.0), the following platforms are
+able to build Perl from the standard source code distribution
+available at http://www.cpan.org/src/index.html
+
+ AIX
+ BeOS
+ Cygwin
+ DG/UX
+ DOS DJGPP 1)
+ DYNIX/ptx
+ EPOC R5
+ FreeBSD
+ HP-UX
+ IRIX
+ Linux
+ MacOS Classic
+ MacOS X (Darwin)
+ MPE/iX
+ NetBSD
+ NetWare
+ NonStop-UX
+ ReliantUNIX (SINIX)
+ OpenBSD
+ OpenVMS (VMS)
+ OS/2
+ POSIX-BC (BS2000)
+ QNX
+ Solaris
+ Tru64 UNIX (DEC OSF/1, Digital UNIX)
+ UNICOS
+ UNICOS/mk
+ UTS
+ VOS
+ WinNT/2000/XP 2)
+ WinCE
+ z/OS (OS/390)
+ VM/ESA
1) in DOS mode either the DOS or OS/2 ports can be used
- 2) Mac OS Classic (pre-X) is almost 5.6.1-ready; building from
- the source does work with 5.6.1, but additional MacOS specific
- source code is needed for a complete build. See the web
- site http://dev.macperl.org/ for more information.
- 3) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++
-
-The following platforms worked for the previous releases (5.6.0 and 5.7.0),
-but we did not manage to test these in time for the 5.7.1 release.
-There is a very good chance that these will work fine with the 5.7.1.
-
- DomainOS
- Hurd
- LynxOS
- MinGW
- MPE/iX
- NetBSD
- PowerMAX
- SCO SV
- SunOS
- SVR4
- Unixware
- Windows 3.1
- Windows 95
- Windows 98
- Windows Me
-
-The following platform worked for the 5.005_03 major release but not
-for 5.6.0. Standardization on UTF-8 as the internal string
-representation in 5.6.0 and 5.6.1 introduced incompatibilities in this
-EBCDIC platform. While Perl 5.7.1 will build on this platform some
-regression tests may fail and the C<use utf8;> pragma typically
-introduces text handling errors.
-
- OS/390 1)
-
- 1) previously known as MVS, about to become z/OS.
-
-Strongly related to the OS/390 platform by also being EBCDIC-based
-mainframe platforms are the following platforms:
-
- POSIX-BC (BS2000)
- VM/ESA
-
-These are also expected to work, albeit with no UTF-8 support, under 5.6.1
-for the same reasons as OS/390. Contact the mailing list perl-mvs@perl.org
-for more details.
+ 2) compilers: Borland, Cygwin (GCC), MinGW (GCC), VC6
+
+The following platforms worked with the previous releases (5.6 and
+5.7), but we did not manage either to fix or to test these in time
+for the 5.8.0 release. There is a very good chance that many of these
+will work fine with the 5.8.0. The only one known for certain to be
+broken for 5.8.0 is the AmigaOS.
+
+ AmigaOS
+ DomainOS
+ Hurd
+ LynxOS
+ MachTen
+ PowerMAX
+ SCO SV
+ SunOS 4
+ SVR4
+ Unixware
+ Windows 3.1
+ Windows 95
+ Windows 98
+ Windows Me
The following platforms have been known to build Perl from source in
the past (5.005_03 and earlier), but we haven't been able to verify
though, so go ahead and try compiling them, and let perlbug@perl.org
of any trouble.
- 3b1
- A/UX
- BeOS
- BSD/OS
- ConvexOS
- CX/UX
- DC/OSx
- DDE SMES
- DOS EMX
- Dynix
- EP/IX
- ESIX
- FPS
- GENIX
- Greenhills
- ISC
- MachTen 68k
- MiNT
- MPC
- NEWS-OS
- NextSTEP
- OpenSTEP
- Opus
- Plan 9
- PowerUX
- RISC/os
- SCO ODT/OSR
- Stellar
- SVR2
- TI1500
- TitanOS
- Ultrix
- Unisys Dynix
- Unixware
- UTS
-
-Support for the following platform is planned for a future Perl release:
-
- Netware
+ 3b1
+ A/UX
+ BSD/OS
+ ConvexOS
+ CX/UX
+ DC/OSx
+ DDE SMES
+ DOS EMX
+ Dynix
+ EP/IX
+ ESIX
+ FPS
+ GENIX
+ Greenhills
+ ISC
+ MachTen 68k
+ MiNT
+ MPC
+ NEWS-OS
+ NextSTEP
+ OpenSTEP
+ Opus
+ Plan 9
+ PowerUX
+ RISC/os
+ SCO ODT/OSR
+ Stellar
+ SVR2
+ TI1500
+ TitanOS
+ Ultrix
+ Unisys Dynix
+ Unixware
+ UTS
The following platforms have their own source code distributions and
-binaries available via http://www.perl.com/CPAN/ports/index.html:
+binaries available via http://www.cpan.org/ports/
- Perl release
+ Perl release
- Netware 5.003_07
- OS/400 5.005_02
- Tandem Guardian 5.004
+ OS/400 5.005_02
+ Tandem Guardian 5.004
The following platforms have only binaries available via
-http://www.perl.com/CPAN/ports/index.html :
+http://www.cpan.org/ports/index.html :
- Perl release
+ Perl release
- Acorn RISCOS 5.005_02
- AOS 5.002
- LynxOS 5.004_02
+ Acorn RISCOS 5.005_02
+ AOS 5.002
+ LynxOS 5.004_02
Although we do suggest that you always build your own Perl from
the source code, both for maximal configurability and for security,
in case you are in a hurry you can check
-http://www.perl.com/CPAN/ports/index.html for binary distributions.
+http://www.cpan.org/ports/index.html for binary distributions.
=head1 SEE ALSO
-L<perlaix>, L<perlapollo>, L<perlamiga>, L<perlbeos>, L<perlbs200>,
+L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>, L<perlebcdic>,
L<perlhurd>, L<perlhpux>, L<perlmachten>, L<perlmacos>, L<perlmint>,
L<perlmpeix>, L<perlnetware>, L<perlos2>, L<perlos390>, L<perlplan9>,
Larry Moore <ljmoore@freespace.net>,
Paul Moore <Paul.Moore@uk.origin-it.com>,
Chris Nandor <pudge@pobox.com>,
-Matthias Neeracher <neeri@iis.ee.ethz.ch>,
+Matthias Neeracher <neeracher@mac.com>,
Philip Newton <pne@cpan.org>,
Gary Ng <71564.1743@CompuServe.COM>,
Tom Phoenix <rootbeer@teleport.com>,
Dan Sugalski <dan@sidhe.org>,
Nathan Torkington <gnat@frii.com>.
-=head1 VERSION
-
-Version 1.50, last modified 10 Jul 2001
projects / p5sagit/p5-mst-13.2.git / blobdiff