Perl文件测试操作员帮助

Question

这是一个非常基本的问题,但我是perl的新手,无法解决问题所在.我只是想隔离目录中的文件,但-d运算符会将所有文件夹内容视为文件...

@contents是我的数组,当我运行它时:

use strict;

if ($ARGV[1]) {
    die("Error: You can only monitor one directory at a time\n");
}

my $directory = $ARGV[0] || die "Error: No directory defined\n";

opendir(DIR, $directory) || die "Error: Can't open dir $directory: $!";
my @contents = readdir(DIR);

foreach my $item(@contents) {
    if (-d $item) { next; }
    print"$item is a file\n"; 
}

closedir (DIR);

我一直收到文件夹和文件.或者,如果我使用-f,我什么也得不到.

编辑:这是输出 -

file01.txt is a file
folder 01  is a file
folder 02 is a file
Screen shot 2010-04-18 at 1.26.17 PM.png is a file

我在OSX上运行它

编辑:dir ls -l输出:

aaron ~/Documents/test: ls -l
total 112
-rw-r--r--@ 1 aaron  staff  51235 18 Apr 13:26 Screen shot 2010-04-18 at 1.26.17 PM.png
-rw-r--r--@ 1 aaron  staff      7 18 Apr 13:26 file01.txt
drwxr-xr-x  3 aaron  staff    102 18 Apr 13:25 folder 01
drwxr-xr-x  2 aaron  staff     68 18 Apr 13:25 folder 02

Answer 1

解

我正在测试'.' 作为目录...你正在测试一些其他目录.然后,相对于当前目录检查从目录中读取的名称.如果我使用其他一些目录名,我几乎可以获得除"."之外的所有内容.和'..'列为文件,无论如何.

如果您在名称前加上$ ARGV [0]的值,您将获得预期的结果:

#!/bin/perl -w

use strict;

if ($ARGV[1]) {
    die("Error: You can only monitor one directory at a time\n");
}

my $directory = $ARGV[0] || die "Error: No directory defined\n";

opendir(DIR, $directory) || die "Error: Can't open dir $directory: $!";
my @contents = readdir(DIR);

foreach my $item(@contents) {
    next if -d "$ARGV[0]/$item";
    print "$ARGV[0]/$item is a file\n"; 
}

closedir (DIR);

以前的尝试解释

这适用于MacOS X:

#!/bin/perl -w
use strict;

my @contents = <*>;

foreach my $item (@contents)
{
    print "== $item\n";
    next if -d $item;
    print "$item is a file\n";
}

测试:

MiniMac JL: perl -c xx.pl
xx.pl syntax OK
MiniMac JL: perl xx.pl
== cproto-4.7g
== fpqsort1
fpqsort1 is a file
== fpqsort1.h
fpqsort1.h is a file
== fpqsort2
fpqsort2 is a file
== fpqsort2.c
fpqsort2.c is a file
== gcc-predef.h
gcc-predef.h is a file
== git-1.6.5.7
== go
== makefile
makefile is a file
== qs-test1.c
qs-test1.c is a file
== qs-test2.c
qs-test2.c is a file
== RCS
== rep-report.txt
rep-report.txt is a file
== select.c
select.c is a file
== soq
== xx.pl
xx.pl is a file
MiniMac JL: 

给出问题中代码的略微修改版本:

#!/bin/perl -w

use strict;

if ($ARGV[1]) {
    die("Error: You can only monitor one directory at a time\n");
}

my $directory = $ARGV[0] || die "Error: No directory defined\n";

opendir(DIR, $directory) || die "Error: Can't open dir $directory: $!";
my @contents = readdir(DIR);

foreach my $item(@contents) {
    print "<<$item>>\n";
    next if -d $item;
    print"$item is a file\n"; 
}

closedir (DIR);

在以前的同一目录上运行它,我得到输出:

Minimac JL: perl yy.pl .
<<.>>
<<..>>
<<cproto-4.7g>>
<<fpqsort1>>
fpqsort1 is a file
<<fpqsort1.h>>
fpqsort1.h is a file
<<fpqsort2>>
fpqsort2 is a file
<<fpqsort2.c>>
fpqsort2.c is a file
<<gcc-predef.h>>
gcc-predef.h is a file
<<git-1.6.5.7>>
<<go>>
<<makefile>>
makefile is a file
<<qs-test1.c>>
qs-test1.c is a file
<<qs-test2.c>>
qs-test2.c is a file
<<RCS>>
<<rep-report.txt>>
rep-report.txt is a file
<<select.c>>
select.c is a file
<<soq>>
<<xx.pl>>
xx.pl is a file
<<yy.pl>>
yy.pl is a file
Minimac JL:

注意Perlish成语' next if -d $item;'.还要注意调试技巧:在遍历数组时打印名称 - 使用'<<'和'>>'来包围名称有助于识别奇怪的副作用(例如名称中的换行符).我仔细检查了提供的代码产生的结果是否相同 - 它确实如此.我正在运行带有Perl库存的MacOS X 10.6.3.