perl ,"w|"的工作流程

1 : #!/usr/local/bin/perl
2 :
3 : open (WOUT, "w|");
4 : $time = ;   根据上下文context $time 存储 w的第一行
5 : $time =~ s/^ *//;
6 : $time =~ s/ .*//;
7 : ; # skip headings line 第二行;表示跳过此行，并指针移往下一行
8 : @users = ;  表示将余下的各行放入@users;
9 : close (WOUT);
10: foreach $user (@users) {
11:   $user =~ s/ .*//;
12: }
13: print ("Current time: $time");
14: print ("Users logged on:\n");
15: $prevuser = "";
16: foreach $user (sort @users) {
17:   if ($user ne $prevuser) {
18:     print ("\t$user");
19:     $prevuser = $user;
20:   }
21: }

    结果输出如下：

Current time: 4:25pm
Users logged on:
  dave
  kilroy
  root
  zarquon