Shell Programming and Scripting

user@host> (/home/user) $   gawk '{
> if($0~/^\[/)
> {
> n =asort(arr)
> for(i=1;i<=n;i++)
> printf "%s\n",arr[i]
> delete arr
> if(temp!=""){print temp}
> print $0
> temp=""
>
> }
> else if($0!~/^\#/)
> {
> arr[substr($0,0,3)]=arr[substr($0,0,3)]$0"\n ";
> }
> else
> {
> temp=$0
> }
> }
>
END{n =asort(arr);for(i=1;i<=n;i++){printf "%s\n",arr[i] };print temp}' test.txt> END{n =asort(arr);for(i=1;i<=n;i++){printf "%s\n",arr[i] };print temp}' test.txt
[groups]
abc =
 abc_read =

bac_read=
 bac=

developer=
 developer_read=

test =
 test_write=

#######################
[abc:/bcd/cde]
@test_write = rw

[bcd:/xyz/yzx]
@test= rw

################
[lmn:/bcd/cde]
  @test_write = rw

[lmn:/xyz/yzx]
  @test= rw

############################
user@host> (/home/user) $ uname -a
SunOS host 5.10 Generic_120011-14 sun4u sparc SUNW,Ultra-250 Solaris
user@host> (/home/user) $ gawk --version
GNU Awk 3.1.5
Copyright (C) 1989, 1991-2005 Free Software Foundation.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
user@host> (/home/user) $

sunnt-x1> gawk '{
if($0~/^\[/)
{
n =asort(arr)
for(i=1;i<=n;i++)
printf "%s\n",arr[i]
delete arr
if(temp!=""){print temp}
print $0
temp=""
}
else if($0!~/^\#/)
{
arr[substr($0,0,3)]=arr[substr($0,0,3)]$0"\n ";
}
else
{
temp=$0
}
}
END{n =asort(arr);for(i=1;i<=n;i++){printf "%s\n",arr[i] };print temp}' test

gawk: cmd. line:4: (FILENAME=test FNR=1) fatal: function `asort' not defined
sunnt-x1> gawk --version
Gnu Awk (gawk) 3.0, patchlevel 0

$ cat script.pl
use strict;
use warnings;

my %group;
my ($begin_grp, $end_grp) = ( qr(^\s*\[(?i:groups)\]\s*$), qr(^\s*#+\s*$) );
my $group_proc = 0;
my ($header, $sep);

while ( <> ) {
    chomp;
    if ( /$begin_grp/ .. /$end_grp/ ) {
        ( $header = $_, next ) if /$begin_grp/;
        ( $sep = $_, next ) if /$end_grp/; 
        s/^\s*(.*)\s*$/$1/;
        push @{$group{ +( substr $_, 0, 3 ) }}, $_;
        $group_proc = 1;
        next;
    }

    if ( $group_proc ) {
        print $header, "\n\n";
        for ( sort keys %group ) {
            print +( join "\n ", @{ $group{$_} } ), "\n\n";
        }
        $group_proc = 0;
        print $sep;
    }

    print "\n" if /^\s*(?:#|\[)/;
    print $_, ( /^#/ ? "": "\n");
    
}

print "\n";
$ perl script.pl infile
[groups]

abc = 
 abc_read =

bac_read=
 bac=

developer=
 developer_read=

test =
 test_write=

#######################
[abc:/bcd/cde]
@test_write = rw

[bcd:/xyz/yzx]
@test= rw

################
[lmn:/bcd/cde]
  @test_write = rw

 [lmn:/xyz/yzx]
  @test= rw

############################