我对Perl完全陌生,我有一段代码让我回来一个空文件处理程序。为什么我的文件处理程序为空? PERL
my $md5dir = "...plib/test/md5sum"; #IN MY PROG, IS THE FULL PATH
opendir(DIR, $md5dir) or die "Can't open directory $md5dir: $!";
my @md5files = grep !/^\.\.?$/, readdir(DIR);
closedir(DIR);
if ( scalar @md5files < 1
|| scalar @md5files > 8
|| (scalar @md5files % 2 != 0))
{
print "Incorrect amount of files in directory. Aborting.\n";
exit 1;
}
else {
for (my $i = 0; ($i < scalar @md5files/2); $i++) {
my $file1 = $md5files[$i];
open(my $fh1, $file1) or die "Fail to open file $file1 $!";
my $file2 = $md5files[ $i + 3 ];
open(my $fh2, $file2) or die "Fail to open file $file2 $!";
print "2.", $file1, " ", $file2, "\n";
my $first1 = substr($file1, 0, 4);
my $first2 = substr($file2, 0, 4);
if (($first1 cmp $first2) == 0) {
if (eof $fh1) { print "No lines\n"; }
else { my $line1 = <$fh1>; print "$line1\n"; }
if (eof $fh2) { print "No lines2\n"; }
else { my $line2 = <$fh2>; print "$line2\n"; }
close $fh1;
close $fh2;
}
} # for
} # else
输出是这样的:
2.SAM5_27-04-2016_11:21:20.md5 SAM5_27-04-2016_11:20:11.md5
No lines
No lines2
2.SAM6_27-04-2016_11:18:25.md5 SAM6_25-04-2016_10:38:38.md5
No lines
No lines2
2.SAM4_27-04-2016_11:19:06.md5 SAM4_27-04-2016_11:17:22.md5
No lines
No lines2
在目录中的md5sum:
:md5sum>ls -la
total 16
drwxrwxr-x 2 ateam ateam 4096 Apr 27 11:24 ./
drwxrwxr-x 4 ateam ateam 4096 Apr 27 11:24 ../
-rw-rw-r-- 1 ateam ateam 63 Apr 27 11:17 SAM4_27-04-2016_11:17:22.md5
-rw-rw-r-- 1 ateam ateam 63 Apr 27 11:19 SAM4_27-04 2016_11:19:06.md5
-rw-rw-r-- 1 ateam ateam 63 Apr 27 11:20 SAM5_27-04-2016_11:20:11.md5
-rw-rw-r-- 1 ateam ateam 0 Apr 27 11:21 SAM5_27-04-2016_11:21:20.md5
-rw-rw-r-- 1 ateam ateam 63 Apr 25 10:38 SAM6_25-04-2016_10:38:38.md5
-rw-rw-r-- 1 ateam ateam 63 Apr 27 11:18 SAM6_27-04-2016_11:18:25.md5
有人可以解释为什么filehandlers都上来了空?我验证了文件的打印。它们都在数组中打印得很好,并且文件处理程序正在打开......由于文件不是空的,还有什么可能是错误的? (以及所有除了一个...)
只是为了查看文件......以防万一。 打开第一个文件,我得到:
03c0cf2ab0da62832bfc6970d4505746 SAM4_27-04-2016_11:17:22.csv
编辑::: 我做了一个小幅调整的文件:
if (($first1 cmp $first2) == 0) {
if (tell($fh1) == -1){ print "No lines\n";}
else {my $line1= <$fh1>; print "$line1\n"; }
if (eof $fh2){ print "No lines2\n";}
else { my $line2= <$fh2>; print "$line2\n"; }
close $fh1; close $fh2;
}
,并得到这个输出,而不是:
2.SAM5_27-04-2016_11:21:20.md5 SAM5_27-04-2016_11:20:11.md5
Use of uninitialized value in concatenation (.) or string at mulftptest line 53.
No lines2
2.SAM6_27-04-2016_11:18:25.md5 SAM6_25-04-2016_10:38:38.md5
Use of uninitialized value in concatenation (.) or string at mulftptest line 53.
No lines2
2.SAM4_27-04-2016_11:19:06.md5 SAM4_27-04-2016_11:17:22.md5
Use of uninitialized value in concatenation (.) or string at mulftptest line 53.
No lines2
本质,我知道这是告诉我,我试图使用“空”变量。但是,我不明白为什么它是空的。
@eballes它默认为“<”,所以我不认为这就是问题所在。尽管为了可读性/可维护性,您应该始终指定它 –
'<:编码(UTF-8)'这件事? –
我试过了,它没有帮助。 –