Perl: list who is on the system

File: whox. pl;
Function: lists who is on the system. If the same user has logged on to the group multiple times;
Description: lists the user logon times, virtual terminal numbers used, and corresponding IP addresses;
Advantage: it is more intuitive than the information displayed by "who-X.

#! /Usr/bin/perl-wuse strict; ######################################## ########## file: whox. PL # function: lists who is on the system. If multiple logon groups are displayed for the same user, # Description: lists the user logon times, virtual terminal numbers, and corresponding IP addresses. # advantages: compared with the information displayed in "who-X", it is more intuitive # version: v0.11 # Time: # modification: # bug1: fixed the problem of listing users logging on through the console; # bug2: fixed the output tty of printf. An error occurred while the IP variable was an UNDEF value. # Author: semi-idle # Test Platform: # sco_sv scosysv 3.2 5.0.6 i386 # Data Structure Description: # % whox_hash = {stores 'Who-x' to extract information of interest; # user => {uses the actual extracted name as the key; # tty => [], # IP => [], # Count => 1, number of users on the same system ;#}, #}###################################### ############ open (whox, "Who-x |") or die "can't open wordcount: $! "; My % whox_hash; while (<whox>) {####################################### ####### bug1: /(^ \ W +) \ s + (\ W +) \ s. * \ s + ((?: \ D ++ \.) + \ D +)/# Time: # Note: if the user logging on to the console does not have an IP address, the matching fails; ######################################## ###### capture description: $1: User Name; $2: virtual terminal number; $3: ipif (/(^ \ W +) \ s + (\ W +) \ s. *(?: $ | \ S + ((?: \ D ++ \.) + \ D +)/) {If (exists $ whox_hash {$1}) {push @ {$ whox_hash {$1} {tty }}, $2; push @ {$ whox_hash {$1} {IP}, $3; $ whox_hash {$1} {count} ++ ;} else {$ whox_hash {$1 }={ tty => [$2], IP => [$3], Count => 1 ,}}} close whox; # formatting the output foreach my $ user (Keys % whox_hash) {my $ COUNT = $ whox_hash {$ user} {count }; # If ($ count> 1) {printf "%-8 S %-8 s", $ user, $ count; my $ J = length $ user; my $ k = length $ count; For (my $ I = 0; $ I <$ count; $ I ++) {####################################### bug2: $ whox_hash {$ user} {tty} [$ I] and so on # Description: printf outputs tty, IP variable is UNDEF value Error # Time: ###################################### printf "%-10 S %-20s \ n ", $ whox_hash {$ user} {tty} [$ I] | '(null)', $ whox_hash {$ user} {IP} [$ I] | '(null) '; printf "%-8 S %-8 s", "" X ($ J), "" X ($ K );}} else {printf "%-8 S %-8 S %-10 S %-20s \ n", $ user, $ count, $ whox_hash {$ user} {tty} [0] | '(null)', $ whox_hash {$ user} {IP} [0] | '(null) ';} print "\ r ";}

The output interface of the original 'Who-x' command:

Page after whox. pl execution:

Bug2:

Bug2 repair: