. '%an' . '%x00' # author name
. '%s' . '%x00' # subject
. '%d'; # ref names
-my $cmd = "git log --all --graph --format='$format'";
-open my $fh, '-|', $cmd or die $!;
+my @cmd = ('git', 'log', '--all', '--graph', "--format=$format");
+open my $fh, '-|', @cmd or die $!;
while (my $line = <$fh>) {
# History graph line.