Question

这一次让我很难过，所以在经过这么多长时间的咖啡之后，我正在接触到我所知道的最好的编码社区，以及多喝咖啡。

基本上我需要一个perl脚本来等待文件在服务器上不再存在，然后再继续。真的在等待所有屏幕会话终止（/ var / run / screen是一个空目录）。

#!/usr/bin/perl
my $directory="/root/screens";

opendir(DIR, $directory) or die "couldn't open $directory: $!\n";
my @files = readdir DIR;
closedir DIR;

foreach (@files){

        while (-e $_) {
        print "$directory has $_ existing\n";
        sleep 1;
        }
}

Ex Dir。

  total 8 
  drwxr-xr-x.  2 root root 4096 Oct 11 22:58 ./ 
  drwxr-x---. 17 root root 4096 Oct 11 05:33 ../
  -rw-r--r--.  1 root root    0 Oct 11 22:58 S-root
  -rw-r--r--.  1 root root    0 Oct 11 22:58 S-root1

上述内容显然不起作用，但我只是没有在Google上看到这样做的好方法，而且这是漫长的一天。

Answer 1

#!/usr/bin/perl
my $directory="./test";

my $no_empty = 1;
my @files = ();
while( $no_empty) {
    opendir(DIR, $directory) or die "couldn't open $directory: $!\n";
    @files = readdir DIR;
    #print @files;
    if(scalar @files == 2) {
        $no_empty = 0;
        last;   ##directory is empty
    } else {
        print "Below files present--";
        @files = grep {$_ !~ /\.{1,2}$/} @files;  ## skip . (current dir) and parent dir (..)
        print join (', ',@files);  ##comma seperated file list
        print "\n";   ##mendetory to flash the output buffer
        sleep 1;
    }
}

print "Start with processing cz dir is empty"

示例运行 -

> Below files present--def, abc 
> Below files present--def, abc 
> Below files present--def, abc 
> Below files present--def, abc 
> Start with processing cz dir is empty

Answer 2

我想只要目录不为空，就需要执行while循环。目标目录为空后，程序将返回。

让我们创建一个子例程来检查目标目录是否为空：

sub isDirEmpty {
        my ($dir) = @_;
        my $file;
        if (opendir my $DFH, $dir) {
                while ( defined ( $file = readdir $DFH) ) {
                        next if $file eq '.' or $file eq '..';
                        closedir $DFH;
                        return 0; #Not Empty
                }
                closedir $DFH;
                return 1; #Empty
        } else {
                return -1; #Doesn't exist
        }
}

无限循环的小测试：

my $targetDir = "/path/to/target/dir";
while (1) {
        my $result = isDirEmpty($targetDir);
        if ($result eq 1) {
                print "Your directory is empty\n";
                last;
        } elsif ($result eq -1) {
                print "There has been an error! please check your lousy code!\n";
        }
}

瞧！

Answer 3

怎么样：

my $directory="/root/screens";
while(<$directory/*>) {
    say "not empty";
    sleep 1;
}

Answer 4

#!/usr/bin/perl
my $directory = "/root/screens";

while(1) {
    my @files = <$directory/*>;
    if($#files == -1) {
        last;
    } else {
        sleep 1;
    }
}

# do some stuff when the directory is empty

Answer 5

#!/usr/bin/perl

my $directory="/root/screens";

opendir(DIR, $directory) or die "couldn't open $directory: $!\n";
@files = readdir DIR;
closedir DIR;

while (@files > 2) ### If @files have more than 2 items. 
{
opendir(DIR, $directory) or die "couldn't open $directory: $!\n";
@files = readdir DIR;
closedir DIR;
sleep (1);
}

print "Directory is now empty and loop has ended";

请注意@files总是有2个项目，因为总会有./和../

等到文件不再是不存在的perl

5 个答案: