Shell Programming and Scripting

sed -n -r '/\\$/ { s/\\$//; H; b; }; x; G; s/\n//g; s/,[ \t]*/,/g; p; s/.//g; h'<input-file

User_Alias      ADMIN1 = horacel,matthes,caseyl,alexl2,jackl,johnnyzh,maheshm,jihuih,davidw,christh,williaml,jasminez

 
sed -n -r '/\\$/ { s/\\$//; H; b; }; x; G; s/\n//g; s/,[ \t]*/,/g; p; s/.//g; h' <input-file | grep ADMIN1|sed 's/^.*= *//; s/,/\n/g'

User_Alias      ADMIN1 = horacel,matthes,caseyl,alexl2,\
                         jackl,johnnyzh,maheshm,jihuih,davidw,\
                         christh,williaml,jasminez

horacel,matthes,caseyl,alexl2,\

horacel,matthes,caseyl,alexl2, jackl,johnnyzh,maheshm,jihuih,davidw,christh,williaml,jasminez

% ADMIN=ADMIN1; perl -lne '$s .= $_;  
  if (!/\\$/) {
        $s =~ s/ |\\//g;
        $s =~ /'$ADMIN'/ && $s =~ s/^.*'$ADMIN'=// && print $s;
        $s=""}' testfile
horacel,matthes,caseyl,alexl2,jackl,johnnyzh,maheshm,jihuih,davidw,christh,williaml,jasminez

#!/usr/bin/perl -Ws

use strict;
use warnings;

local $/;
our $group;

my $file = <>;

if ( $file =~ /User_Alias\s+$group\s+=\s+(.+?)[^\\]$/ms ) {
    my $users = $1;
    $users =~ s/[\n \\]//g;
    print $users, "\n";
}