求助：一个关于替换操作符的问题

wellshunan

CODE:
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#!/usr/local/bin/perl

open(WOUT,"w|";
$time = <WOUT>;
$time =~s/^ *//;
$time =~s/ .*//;
close(WOUT);
print("Current timetime";
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w命令列出当前时间、系统负载和登录的用户，以及每个用户的作业时间和当前运行的命令，如：
  4:25pm  up 1 day,  6:37,  6 users,  load average: 0.79, 0.36, 0.28
其中的$time =~s/ .*//;删去除时间和结尾换行符之间的所有字符，存入变量$time。
我不知道时间段怎么保留的，麻烦指点下，想老久了。谢谢！！




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万事开头难啊

ulmer

Hallo,

before processing output's data from command "w", you should study the STDOUT from "w":
i.e: under my linuxbox:

1. 
   
2. shell> w
   
3.   10:04:56 up 22 days, 23:25, 15 users,  load average: 0,05, 0,08, 0,02
   
4. USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
   
5. foo    :0       -                19Jun06 ?xdm?  24:29m  9.14s /usr/bin/gnome-session
   
6. foo    pts/0    :0.0             19Jun06  4days  0.06s  0.06s bash
   
7. ...
   

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Output from "w" without additional options:
Fisrt line is summary message
Second line is field's title (8 fields or columns)
Rest lines are records with "\s+" seperated.

Howto processing this output? => improving your code:
1. read filehandle <WOUT> into an array.
2. Loop this array and deal with each line
3. using split() to fetch each field per line.
4. then processing those field which you want furtherly.

Sample code:

1. 
   
2. open WOUT, "w|";
   
3. @w = <WOUT>;
   
4. close WOUT;
   
5. 
   
6. $w_summary = $w[0];  # to process 1. line
   
7. $w_field_title = $w[1];  # to process 2. line
   
8. 
   
9. # fetch w's records started fron third. line ...
   
10. foreach my $line (@w[2..$#w]) {
    
11.     # must set total colmns in spilt exactly 8
    
12.     ($USER, $TTY, $FROM, $LOGIN, $IDLE, $JCPU, $PCPU, $WHAT) = split(/\s+/, $line, 8);
    
13.     # processing field: i.e.:
    
14.     # your homework
    
15.     print "DEBUG; $LOGIN, $WHAT";}';
    
16. }
    
17. 
    

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Best,
    ulmer

--------
Just 4 Fun

wellshunan

Thank you!