Shell Programming and Scripting

cat abc.txt | perl -e 'while(<>){
chomp;
my $pos_to_remove = 4; # change this position as per ur req
print substr($_,0,($pos_to_remove-1)).substr($_,$pos_to_remove)."\n";
}'

 cat abc.txt | perl -e 'while(<>){ chomp;
my $pos_to_remove = 3;
s/(.{$pos_to_remove}).(.*)/$1$2/g;
print "$_\n";
}'

$ cat t
GETR P123456
GET P:=12345
sdflkj sdfkj

$ cat t.pl
while(<>)  {
s/^((GETR P|GET P:=).{3}).(.*)$/\1\3/;
print;
}

perl -i t.pl t

$ cat t
GETR P12356
GET P:=1235
sdflkj sdfkj