ANTICHAT — форум по информационной безопасности, OSINT и технологиям

open(DAT, "gnu1.txt") || die("error1!");
@data=<DAT>;
close(DAT);

open(FILE, ">>gnu2.txt") || die("error2!");
foreach $line (@data)
     {
     my($a,$b) = split(/;/, $line);
     print FILE  "$a;$b\n";
     }
close(FILE);

open(DAT, "<gnu1.txt") || die $!;
@data=<DAT>;
close(DAT);

open(FILE, ">>gnu2.txt") || die $!;
foreach(@data)
     {
	 $_=~ /(.+);/ ? print FILE $1."\n" : ();
     }
close(FILE);

$ cat test.txt
line1;aaaaa
line2;bbbbbb
line3;ccc
line4;dddd
$ perl -ne '/(.+)(;.+)(?{ print "$1;${\substr($2,int length($2)\/2)}\n" })/' file.txt
line1;aaa
line2;bbbb
line3;cc
line4;ddd
$

$ cat file
line1;aaaaa
line2;bbbbbb
line3;ccc
line4;dddd
line5
$ perl -F\; -nae 'print $F[1]||$F[0]' file
aaaaa
bbbbbb
ccc
dddd
line5
$