> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/perl6-rosettacode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/perl6-rosettacode/programming_tasks/t/truncate_a_file.md).

# Truncate a file

```perl
use NativeCall;

sub truncate(Str, int32 --> int32) is native {*}

sub MAIN (Str $file, Int $to) {
    given $file.IO { 
        .e        or die "$file doesn't exist";
        .w        or die "$file isn't writable";
        .s >= $to or die "$file is not big enough to truncate";
    }
    truncate($file, $to) == 0 or die "Truncation was unsuccessful";
}
```

The external `truncate` routine could be replaced with the following line (in which case no need for `NativeCall`):

```perl
spurt $file, slurp($file).substr($to);
```