- Perlについての質問箱 64箱目 [転載禁止]©2ch.net
778 ：デフォルトの名無しさん[sage]：2015/12/19(土) 02:05:18.10 ID:akpvQEZV - >>775-776
1行ずつではなく追加する行のバイト長ずつだが
#!/usr/bin/perl
use strict; use warnings; use Fcntl qw(LOCK_EX SEEK_CUR);
my $ow_line = "append line to top of file.\n";
my $ow_len = length $ow_line;
open my $fh, '+<', $ARGV[0] or die $!;
flock $fh, LOCK_EX or die $!;
binmode $fh;
while (my $buf_len = sysread $fh, my $buf_line, $ow_len) {
sysseek $fh, -$buf_len, SEEK_CUR;
syswrite $fh, $ow_line;
$ow_line = $buf_line;
$ow_len = $buf_len;
}
syswrite $fh, $ow_line;
close $fh or die $!;
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