riywo

# diff -u /usr/bin/innobackupex-1.5.1 innobackupex-1.5.1 
--- /usr/bin/innobackupex-1.5.1 2010-11-12 16:13:38.000000000 +0900
+++ innobackupex-1.5.1  2011-03-14 13:17:24.000000000 +0900
@@ -1134,7 +1134,8 @@
     my $options = get_mysql_options();
     # run mysql as a child process with a pipe connection
     $now = current_time();
-    print STDERR "$now  $prefix Starting mysql with options: $options\n";
+    (my $prt_options = $options) =~ s/--password=[^ ]+ /--password=xxxxxxxx /g;
+    print STDERR "$now  $prefix Starting mysql with options: $prt_options\n";

riywo

use strict;
use warnings;

use Furl;
use JSON;
use Encode;
use Web::Scraper;

my $furl = Furl->new;
my $scraped = scraper {

riywo

find /path/to/dir/ -type f | time parallel --eta 'rsync -aRz --compress-level=1  {} remote:/'

riywo

use strict;
use warnings;
use IO::Handle;

my ($parent_in, $parent_out);
my ($child_in, $child_out);

pipe $parent_out, $child_in;
pipe $child_out, $parent_in;

riywo

See also perlipc - Perl のプロセス間通信 (シグナル, fifo, パイプ, 安全な副プロセス, ソケット, セマフォ) 【perldoc.jp】

単純に実行だけしたい

system "$CMD";

標準入力を操作したい

open $in, "| $CMD";
print $in "hoge";
close $in;

riywo

mysql> select * from microsec limit 10;
+------------+--------+
| epoch      | us     |
+------------+--------+
| 1300337288 | 938208 |
| 1300337288 | 965069 |
| 1300337288 | 976498 |
| 1300337288 | 987483 |
| 1300337288 | 998476 |
| 1300337289 |   9421 |

riywo

tail -fみたいに流しながら見たいんだけど、色んなコマンドが出力をバッファしちゃうので、困ったときはそのコマンドにバッファしないオプションが無いか探すのがオヌヌメ。 man command -> bufferとかで検索

grep

   --line-buffered
          Use line buffering, it can be a performance penality.

$ iostat -x 1 | grep --line-buffered 'sda'

awk

riywo

my $ret = $mysql->mysql("select count(*) from $TABLE", 'db' => $DB, 'opt' => "--skip-column-name"),
note($ret);
note explain $ret;
is($ret, "200\n", "count");
note($ret);

#---------------------------------------------------------------------------------------------------

# undef
# 100

riywo

use strict;
use warnings;
use Data::Dumper;
use IO::Handle;

my ($parent_in, $parent_out);
my ($child_in, $child_out);
pipe $parent_out, $child_in;
pipe $child_out, $parent_in;
$parent_in->autoflush(1);

riywo

use strict;
use warnings;
use IO::Handle;

sub fork_exec {
    my @args = @_;
    my $handles = [];

    if (ref($args[$#args]) eq 'GLOB') {
        my $stdin = pop @args;