This awk code will delete character at position specified by NUM
Code:
BEGIN { NUM = 13 }
{
if ( NUM > length($0) ) {
NUM = NUM - length($0)
print
}
else {
printf "%s",substr($0,1,NUM-1)
print substr($0,NUM+1)
NUM = 1e+15
}
}
It considers the character position as absolute inside the whole text (not the position on each line) including blank spaces and tabs in the count and excluding newline characters \n.