倒回檔案控制代碼
有時需要在閱讀後回溯。
# identify current position in file, in case the first line isn't a comment
my $current_pos = tell;
while (my $line = readline $fh)
{
if ($line =~ /$START_OF_COMMENT_LINE/)
{
push @names, get_name_from_comment($line);
}
else {
last; # break out of the while loop
}
$current_pos = tell; # keep track of current position, in case we need to rewind the next line read
}
# Step back a line so that it can be processed later as the first data line
seek $fh, $current_pos, 0;