## Copyright (C) 1998 Hrvoje Niksic
## Modification by Zeljko Boros (block entries, removing old entries)
## More options and use strict by Zoran Dzelajlija on 2004-02-24
+## Quite a few improvements by Damir Dzeko on 2005-03-18 (see bellow)
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## along with this program; if not, write to the Free Software
## Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-## $Id: cp-update,v 2.2 2004/02/24 jelly Exp $
+## altered by ddzeko, 2005-03-18
+## -> reformated code, introduced coding conventions
+## -> increased reliability through atomic actualization
+## -> everything is done in the memory - more mem, less i/o
+## -> removed append mode - in-place editing considered harmful
+## -> added in-place mode as option
use strict;
+use Fcntl qw(:DEFAULT :flock :seek);
-my ($name, $usage);
-
-($name = $0) =~ s%.*/%%; # Looks nicer without the slashes
-$usage = "Usage:\n";
-$usage .= "$name [-r] [-m] [-i AFTER|-t] [-b START -e STOP] [-c CHAR] PACKAGE FILE\n";
-$usage .= " -r Remove entry PACKAGE from FILE\n";
-$usage .= " Default is to add lines from stdin.\n";
-$usage .= " -m Allow multiple blocks of the same type\n";
-$usage .= " By default, old blocks are replaced with the new one.\n";
-$usage .= "\n";
-$usage .= " Special placement of config blocks:\n";
-$usage .= " -i Insert after this line\n";
-$usage .= " -t Insert on top\n";
-$usage .= " The default is to append at the bottom.\n";
-$usage .= "\n";
-$usage .= " Manipulating block marks:\n";
-$usage .= " -c Use alternative comment character (default: #)\n";
-$usage .= " Alternative block marks:\n";
-$usage .= " -b Start mark (ie 'service ftp')\n";
-$usage .= " -e Stop mark (ie. '}')\n";
-$usage .= " These will delete to the end of the file if no end mark\n";
-$usage .= " is found. The deletion is otherwise not greedy and\n";
-$usage .= " stops at the first end mark found. You can use\n";
-$usage .= " %P to insert the PACKAGE argument, and\n";
-$usage .= " %% to insert a literal % sign into the mark.\n";
-
-
-
-
-my ($begin, $end, $trailer);
-my ($parambegin, $paramend, $insert);
-my ($pkg, $file);
-my ($block, $multi, $addafter, $addontop);
-
-my $add = 1;
-my $comment = "#";
-my $SEEK_END = 2;
-
-while (@ARGV)
-{
- $_ = shift;
- if (/^-c$/ || /^--comment$/)
- {
- defined ($comment = shift)
- || die "$name: `-c' must be followed by an argument\n";
- }
- elsif (/^-r$/ || /^--remove$/)
- {
- $add = 0;
- }
- elsif (/^-m$/ || /^--allow-multiple$/)
- {
- $multi = 1;
- }
- elsif (/^-b$/ || /^--begin$/)
- {
- defined ($parambegin = shift)
- || die "$name: '-b' must be followed by an argument\n";
- $block = 1;
- }
- elsif (/^-e$/ || /^--end$/)
- {
- defined ($paramend = shift)
- || die "$name: '-e' must be followed by an argument\n";
- $block = 1;
- }
- elsif (/^-i$/ || /^--insert-after$/)
- {
- defined($insert = shift)
- || die "$name: '-i' must be followed by an anrgument\n";
- #$multi = 1; # uncomment for -i backward compatibility
- $addafter = 1;
- }
- elsif (/^-t$/ || /^--insert-on-top$/)
- {
- $insert = "";
- $addafter = 1;
- }
- elsif (/^-/)
- {
- die "$name: Unrecognized option \`$_'\n";
- }
- else
- {
- unshift(@ARGV, $_);
- last;
- }
+sub DEBUG () { 0 };
+
+# coding convention: CamelCase vars are global here
+#
+my ($ProgramName, $UsageLong, $UsageShort, $VERSION);
+
+$VERSION = '2.1';
+
+# Looks nicer without the slashes and dots
+($ProgramName = $0) =~ s!.*/!!; # strip dir
+$ProgramName =~ s!\.[^.]+$!!; # strip last ext
+
+# 34567890 34567890 34567890 34567890 34567890 34567890 34567890 345678
+
+$UsageLong = "
+ $ProgramName -- versatile line-based file updating tool
+ usually used by package configuration scripts
+
+ Usage: $ProgramName [options] PACKAGE FILE < stdin-content
+
+
+ - General options:
+
+ -r | --remove Remove entry PACKAGE from FILE.
+ Default is to add lines from stdin.
+
+ -x | --change Modify existing block, or add it if
+ it does not exist but the begin mark
+ can be found.
+
+ -m | --allow-multiple Allow multiple blocks of the same type.
+ By default, old blocks are replaced with
+ the new one.
+
+ -h | --help Print this message (usage reference).
+
+ --version Print version message.
+
+ - Placement control:
+
+ -t | --insert-on-top Insert stdin-content block on top.
+ The default is to add it at the bottom.
+
+ -i | --insert-after x Insert after this/matching line.
+ -f | --insert-before x Insert before this/matching line.
+
+ - Manipulating block marks:
+
+ -c | --comment x Use alternative comment char/string.
+ The default is shell-style \#-sign.
+
+ --comment-end x Use this marker for comment ending.
+ The default is none. Ie. '-->', '*/'.
+
+ -b | --begin-mark x Block starting mark (ie. 'service ftp')
+ -e | --end-mark x Block ending mark (ie. '}')
+
+ These will delete to the end of the file if no end mark
+ is found. The deletion is otherwise not greedy and stops
+ at the first end mark found. You can use \%P to insert
+ the PACKAGE argument, and \%\% to insert a literal \% sign
+ into the mark.
+
+ - File handling options:
+
+ -p | --in-place Try to preserve original inode.
+ -n | --no-close Do not close and reopen file when
+ editing it in place.
+
+ Options marked with 'x' take single argument. Others do not.
+
+\n";
+
+$UsageShort = "$ProgramName -- versatile line-based file updating tool\n";
+$UsageShort .= " Options: [-r] [-m] [-i AFTER|-f BEFORE|-t] [-b START -e STOP] [-c CHAR] PACKAGE FILE\n";
+$UsageShort .= " or type $ProgramName --help to be choked with help.\n";
+
+my ($MarkBegin, $MarkEnd, $Trailer, $ParamBegin, $ParamEnd, $Placement,
+ $Package, $File, $Block, $Multi, $InsertRemove, $Comment, $CommentEnd,
+ $MatchLine, $RegexpMatch, $StdinContent, $NewContent, $InPlace,
+ $NoClose, $FileHandle, @Lines, $LinesCount);
+
+# Placement modes
+use constant APPEND_AT_END => 0;
+use constant INSERT_BEFORE => 1;
+use constant INSERT_AFTER => 2;
+use constant INSERT_ON_TOP => 3;
+
+# InsertRemove modes
+use constant DO_REMOVE => 0;
+use constant DO_INSERT => 1;
+use constant DO_CHANGE => 2;
+
+# Operation defaults
+$InsertRemove = DO_INSERT;
+$Placement = APPEND_AT_END;
+$RegexpMatch = 1;
+$Comment = '#';
+$CommentEnd = '';
+$MatchLine = '';
+$InPlace = 0;
+$NoClose = 0;
+
+while (@ARGV) {
+ $_ = shift;
+ if (/^-c$/ || /^--comment$/) {
+ defined ($Comment = shift)
+ || die "$ProgramName: `-c|--comment' must be followed by an argument\n";
+ }
+ elsif (/^--comment-end$/) {
+ defined ($CommentEnd = shift)
+ || die "$ProgramName: `--comment-end' must be followed by an argument\n";
+ }
+ elsif (/^-r$/ || /^--remove$/) {
+ $InsertRemove = DO_REMOVE;
+ }
+ elsif (/^-x$/ || /^--change$/) {
+ $InsertRemove = DO_CHANGE;
+ }
+ elsif (/^-m$/ || /^--allow-multi(?:ple)?$/) {
+ $Multi = 1;
+ }
+ elsif (/^-b$/ || /^--begin(?:-mark)?$/) {
+ defined ($ParamBegin = shift)
+ || die "$ProgramName: '-b|--begin-mark' must be followed by an argument\n";
+ $Block = 1;
+ }
+ elsif (/^-e$/ || /^--end(?:-mark)?$/) {
+ defined ($ParamEnd = shift)
+ || die "$ProgramName: '-e|--end-mark' must be followed by an argument\n";
+ $Block = 1;
+ }
+ elsif (/^-i$/ || /^--insert-after$/) {
+ defined($MatchLine = shift)
+ || die "$ProgramName: '-i|--insert-after' must be followed by an argument\n";
+ $Placement = INSERT_AFTER;
+ }
+ elsif (/^-f$/ || /^--insert-before$/) {
+ defined($MatchLine = shift)
+ || die "$ProgramName: '-f|--insert-before' must be followed by an argument\n";
+ $Placement = INSERT_BEFORE;
+ }
+ elsif (/^-t$/ || /^--insert-on-top$/) {
+ $Placement = INSERT_ON_TOP;
+ }
+ elsif (/^-R$/ || /^--regexp(?:-match|-mode)?$/) {
+ $RegexpMatch = 1; # it's the default
+ }
+ elsif (/^-h$/ || /^--help$/) {
+ die $UsageLong;
+ }
+ elsif (/^-p$/ || /^--in-place$/) {
+ $InPlace = 1;
+ }
+ elsif (/^-n$/ || /^--no-close$/) {
+ $NoClose = 1;
+ }
+ elsif (/^--version$/) {
+ die "$ProgramName (CARNet Packaging file update) $VERSION\n"
+ . "Copyright (C) 1998-2005 Free Software Foundation, Inc.\n"
+ . "This is free software; see the source for copying conditions. There is NO\n"
+ . "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n";
+ }
+ elsif (/^-/) {
+ die "$ProgramName: Unrecognized option \`$_'\n";
+ }
+ else {
+ unshift(@ARGV, $_);
+ last;
+ }
+
+ if ($Multi and DO_CHANGE == $InsertRemove) {
+ die "$ProgramName: Cannot use both `--change' and `--allow-multiple'\n";
+ }
+}
+
+$Package = shift or die $UsageShort;
+$File = shift or die $UsageShort;
+
+# prepare block begin and end marks
+#
+(! $Block || ($ParamBegin && $ParamEnd))
+ or die ("$ProgramName: must provide both begin and end marks.\n");
+#
+if ($Block) {
+ $ParamBegin =~ s, %P , $Package ,gx;
+ $ParamBegin =~ s, %% , % ,gx;
+ $ParamEnd =~ s, %P , $Package ,gx;
+ $ParamEnd =~ s, %% , % ,gx;
+ $MarkBegin = $ParamBegin;
+ $MarkEnd = $ParamEnd;
+ $Trailer = '';
+} else {
+ $MarkBegin = "$Comment Begin update by CARNet package $Package";
+ $MarkEnd = "$Comment End update by CARNet package $Package";
+ $Trailer = " -- DO NOT DELETE THIS LINE!".$CommentEnd;
}
-($pkg = shift) || die $usage;
-($file = shift) || die $usage;
-(! $block || ($parambegin && $paramend))
- || die ("$name: must provide both begin and end marks.\n");
-
-if ($block)
-{
- $parambegin =~ s,%P,$pkg,g;
- $parambegin =~ s,%%,%,g;
- $paramend =~ s,%P,$pkg,g;
- $paramend =~ s,%%,%,g;
- $begin = $parambegin;
- $end = $paramend;
- $trailer = "";
+DEBUG and print STDERR "MarkBegin='$MarkBegin'\nMarkEnd='$MarkEnd'\nTrailer='$Trailer'\n";
+
+# compile regexp if provided
+#
+if ($RegexpMatch) {
+ # compile user's regexp
+ eval { $MatchLine = qr<$MatchLine> };
+}
+else {
+ # we'll do regexp matching anyway :)
+ # just not with user's specials interfering
+ eval { $MatchLine = qr<^\Q$MatchLine\E>o; };
}
-else
-{
- $begin = "$comment Begin update by CARNet package $pkg";
- $end = "$comment End update by CARNet package $pkg";
- $trailer = " -- DO NOT DELETE THIS LINE!";
+if ($@) {
+ die "$ProgramName: regexp compilation failed: $@ ($!)\n";
}
-if ($add)
-{
- if (! $multi)
- {
- &del;
- }
- &add;
+do_it() and exit(0);
+
+
+# main procedure
+# --------------
+
+sub do_it {
+ $LinesCount = slurp();
+ if (DO_CHANGE == $InsertRemove) {
+ $StdinContent = &stdin_content;
+ change() or add();
+ }
+ elsif (DO_INSERT == $InsertRemove) {
+ $StdinContent = &stdin_content;
+ del() unless $Multi;
+ add();
+ }
+ else {
+ del();
+ }
+ actualize();
}
-else
-{
- &del;
+
+
+# subroutines
+# -----------
+
+sub slurp() {
+ sysopen($FileHandle, $File, O_RDWR) or die "$ProgramName: Cannot open $File: $!\n";
+ @Lines = <$FileHandle>; # slurp the whole file as lines
+ close($FileHandle) unless ($InPlace && $NoClose);
+
+ # If FILE does not have a trailing newline, be sure to add it
+ # before appending anything else.
+ if (@Lines and $Lines[$#Lines] !~ m/\n$/s) {
+ $Lines[$#Lines] .= "\n";
+ }
+
+ return scalar @Lines;
}
sub add() {
- $trailer .= "\n";
- $begin .= $trailer;
- $end .= $trailer;
- my $byte = ""; # @#$@#$@#$$@#$@#$#@$! -w
- my $prefix = "";
-
- open (HANDLE, "<$file") || die "$file: $!\n";
-
- # Need to load it all into memory if we want to write it
- # out to the same file.
- my @lines = <HANDLE> if ($addafter);
-
- # If FILE does not have a trailing newline, be suire to add it
- # before appending anything else.
-
- # Unless it is size 0!
- if ((-s $file))
- {
- seek HANDLE, -1, $SEEK_END;
- defined (read HANDLE, $byte, 1) && ($byte ne "\n") && ($prefix = "\n");
- close HANDLE;
- }
-
- if(!$addafter)
- {
- # The actual work is in the following three lines:
- open (HANDLE, ">>$file") || die "$file: $!\n";
- print HANDLE $prefix . $begin . join('', <STDIN>) . $end;
- close HANDLE;
- }
- else
- {
- # Overwrite it
- open (HANDLE, ">$file") || die "$file: $!\n";
- my $added = 0;
- foreach (@lines)
- {
- if (! $added && /^$insert/o)
- {
- print HANDLE if ($insert ne "");
- print HANDLE $begin . join('', <STDIN>) . $end;
- print HANDLE if ($insert eq "");
- $added = 1;
- }
- else
- {
- print HANDLE;
- }
+ if (APPEND_AT_END == $Placement) {
+ # append stuff at the end of the file
+ push(@Lines, $StdinContent);
+ }
+ elsif (INSERT_ON_TOP == $Placement) {
+ # throw the stuff on top of the file
+ unshift(@Lines, $StdinContent);
+ }
+ else {
+ # insert stuff where needed
+ my ($line, $lineNo, $added);
+ $lineNo = 0;
+ $added = 0;
+ foreach $line (@Lines) {
+ DEBUG and print STDERR "at: $line";
+ if ($line =~ m/$MatchLine/) {
+ DEBUG and print STDERR " - MATCH\n";
+ if (INSERT_AFTER == $Placement) {
+ DEBUG and print STDERR " - INSERT_AFTER\n";
+ splice(@Lines, $lineNo + 1, 0, $StdinContent);
}
- if(! $added)
- {
- print HANDLE $prefix . $begin . join('', <STDIN>) . $end;
+ elsif (INSERT_BEFORE == $Placement) {
+ DEBUG and print STDERR " - INSERT_BEFORE\n";
+ splice(@Lines, $lineNo, 0, $StdinContent);
}
- close HANDLE;
+ # once added and we're done
+ $added = 1;
+ last;
+ }
+ ++ $lineNo;
+ }
+ if ($MatchLine and ! $added) {
+ warn "$ProgramName: Inserting lines at the end implicitly! No '$MatchLine'\n";
+ push(@Lines, $StdinContent);
}
+ }
+ # add the number of lines in added content to safety counter
+ $LinesCount += ($StdinContent =~ tr/\n//);
+ return $LinesCount; # whatever true
}
sub del() {
- # saving vars for &add function...
- my ($mybegin, $myend, $mytrailer);
-
- $mybegin = $begin;
- $myend = $end;
- $mytrailer = $trailer;
-
- # Make the strings regexp-friendly by quoting non-word chars.
- $mybegin =~ s/\W/\\$&/g;
- $myend =~ s/\W/\\$&/g;
- $mytrailer =~ s/\W/\\$&/g;
- open (HANDLE, "<$file") || die "$file: $!\n";
- # Need to load it all into memory, because we'll want to write it
- # out to the same file.
- my @lines = <HANDLE>;
- close HANDLE;
- open (HANDLE, ">$file") || die "$file: $!\n";
- foreach (@lines)
- {
- print HANDLE unless (/^$mybegin(?:$mytrailer)?$/o
- .. /^$myend(?:$mytrailer)?$/o);
+ my ($mytrailer, $mybegin, $myend) =
+ ($Trailer, $MarkBegin, $MarkEnd);
+
+ my ($bm_found, $em_found); # begin/end mark found indicator
+
+ # Make the strings regexp-friendly by quoting non-word chars.
+ $mybegin =~ s/\W/\\$&/g;
+ $myend =~ s/\W/\\$&/g;
+ $mytrailer =~ s/\W/\\$&/g;
+
+ my (@filtered);
+ foreach (@Lines) {
+ if (/^$mybegin(?:$mytrailer)?$/o .. /^$myend(?:$mytrailer)?$/o) {
+ # additional safety counter for double-check
+ -- $LinesCount;
+ } else {
+ push (@filtered, $_);
}
- close HANDLE;
+ # for safety check:
+ $bm_found = 1 if (/^$mybegin(?:$mytrailer)?$/o);
+ $em_found = 1 if (/^$myend(?:$mytrailer)?$/o);
+ }
+ if ($bm_found and $em_found) {
+ DEBUG and print STDERR "Deleted ". (@Lines - @filtered) ." out of ".scalar(@Lines)." lines\n";
+ @Lines = @filtered;
+ }
+ elsif ($bm_found and ! $em_found) {
+ # safety exit
+ die "$ProgramName: no end-mark after begin-mark!\n";
+ }
+ return $LinesCount; # whatever
+}
+
+sub change() {
+ my ($mytrailer, $mybegin, $myend) =
+ ($Trailer, $MarkBegin, $MarkEnd);
+
+ my ($bm_found, $em_found); # begin/end mark found indicator
+
+ # Make the strings regexp-friendly by quoting non-word chars.
+ $mybegin =~ s/\W/\\$&/g;
+ $myend =~ s/\W/\\$&/g;
+ $mytrailer =~ s/\W/\\$&/g;
+
+ my (@filtered, $done, $skip);
+ $done = 0; # job done once
+ $skip = 0; # skip original block
+ foreach (@Lines) {
+ if (! $done and $skip > 0) {
+ -- $LinesCount;
+ if (/^$myend(?:$mytrailer)?$/o) {
+ ++ $done; # skipped all that was to skip
+ } else {
+ ++ $skip; # count lines being skipped
+ }
+ }
+ elsif (0 == $skip and $_ =~ /^$mybegin(?:$mytrailer)?$/o) {
+ push (@filtered, $StdinContent);
+ $LinesCount += ($StdinContent =~ tr/\n//);
+ $skip = 1;
+ }
+ else {
+ push (@filtered, $_)
+ }
+ # for safety check:
+ $bm_found = 1 if (/^$mybegin(?:$mytrailer)?$/o);
+ $em_found = 1 if (/^$myend(?:$mytrailer)?$/o);
+ }
+ if ($bm_found and $em_found) {
+ -- $skip; # correct the counter
+ DEBUG and print STDERR "Replaced block of $skip lines\n";
+ @Lines = @filtered;
+ }
+ elsif ($bm_found and ! $em_found) {
+ # safety exit
+ die "$ProgramName: no end-mark after begin-mark!\n";
+ }
+ return $done;
+}
+
+# written by ddzeko@srce.hr, 2005-03-18
+# to improve reliabilitah :)
+#
+sub actualize() {
+ # put it all thogether
+ my $newContent = join('', @Lines);
+
+ unless (length($newContent) or 0 == $LinesCount) {
+ # safety exit in last second :)
+ die "$ProgramName: New content empty -- aborting file alteration!\n";
+ }
+
+ if ($InPlace) {
+ # Provdided as means of changing the file content
+ # and keeping it's inode number still.
+ # -------------------------------------------------------
+ # this is dangerous since it can leave file in bad state
+ # do not use this for highly critical files (ie. inittab)
+ # -------------------------------------------------------
+ # (REVISIT: add File::Copy call to back-up the file so
+ # we can at least try undoing the file content change)
+ # backup_copy();
+ unless (fileno($FileHandle)) {
+ sysopen($FileHandle, $File, O_WRONLY|O_TRUNC)
+ or die "$ProgramName: Failed to open file '$File' for writing ($!)\n";
+ }
+ else {
+ sysseek(*$FileHandle, 0, SEEK_SET)
+ or die "$ProgramName: Failed to seek to the begining of file ($!)\n";
+ }
+ if (length($newContent)) {
+ my $wb = syswrite($FileHandle, $newContent);
+ if (! $wb or length($newContent) != $wb) {
+ # FIXME: try restoring backup copy
+ my $ncl = length($newContent);
+ die "$ProgramName: Failed to write the content to '$File' (wb=$wb, len=$ncl, err:$!)\n";
+ }
+ }
+ if ($NoClose) {
+ # this could be handy for files that had stuff appended
+ # at the end of the file
+ truncate($FileHandle, length($newContent))
+ or die "$ProgramName: Failed to truncate the file ($!)\n";
+ }
+ close($FileHandle);
+ }
+ else {
+ my ($file_new, $file_old) = ($File, $File);
+ $file_new .= '.cp-update.new'; # our .new file
+ $file_old .= '.cp-update.old'; # our .old file
+ # write content in new file in single write op
+ sysopen ($FileHandle, $file_new, O_CREAT|O_TRUNC|O_WRONLY, (stat($File))[2])
+ or die "$ProgramName: Failed to open file '$File' for writing ($!)\n";
+ if (length($newContent)) {
+ my $wb = syswrite($FileHandle, $newContent);
+ if (! $wb or length($newContent) != $wb) {
+ unlink($file_new);
+ my ($ncl) = length($newContent);
+ die "$ProgramName: Failed to write the content to '$File' (wb=$wb, len=$ncl, err:$!)\n";
+ }
+ }
+ close($FileHandle);
+ # do the moving (should be atomic)
+
+ eval { require File::Copy; };
+ if ($@) {
+ # do it the classical way: successive renames
+ rename($File, $file_old)
+ or die "$ProgramName: Failed to rename file '$File' to '$file_old' ($!)\n";
+ }
+ else {
+ import File::Copy;
+ # do it with increased safety: overstepping
+ # the old file with it's modified copy
+ copy($File, $file_old)
+ or die "$ProgramName: Failed to create backup of '$File' as '$file_old' ($!)\n";
+ # if the filesystem is absolutelly filled up this will fail
+ # and the original file will remain unchanged
+ }
+ rename($file_new, $File)
+ or die "$ProgramName: Failed to rename file '$file_new' to '$File' ($!)\n";
+ unlink($file_old)
+ or warn "$ProgramName: Failed to remove file '$file_old' ($!)\n";
+ }
+ DEBUG and print STDERR "actualize: LinesCount=$LinesCount\n";
+}
+
+# return content from standard input
+sub stdin_content() {
+ my ($stdin_content) = join('', <STDIN>);
+ unless (length($stdin_content)) {
+ die "$ProgramName: No stdin-content provided!\n";
+ }
+ if ($stdin_content !~ m/\n$/s) {
+ # add trailing newline
+ $stdin_content .= "\n";
+ }
+
+ my ($mytrailer, $mybegin, $myend) =
+ ($Trailer, $MarkBegin, $MarkEnd);
+
+ $mytrailer .= "\n";
+ $mybegin .= $mytrailer;
+ $myend .= $mytrailer;
+
+ $stdin_content = ($mybegin . $stdin_content . $myend);
+ return $stdin_content;
+}
+
+# create backup copy of altered file
+sub backup_copy() {
+ die "$ProgramName: backup_copy() not implemented";
}
projects / carnet-tools-cn.git / blobdiff