From: Tamara Temple <tamouse.lists@...>
Date: 2013-06-26T10:30:59+09:00
Subject: Re: exec iterate through array

Micah Seattle <lists@ruby-forum.com> wrote:
> mysqldump: Got error: 1044: Access denied for user 'root'@'localhost' to
> database 'information_schema' when using LOCK TABLES

Read the mysqldump man page:

       mysqldump does not dump the INFORMATION_SCHEMA database by default.  mysqldump dumps
       INFORMATION_SCHEMA only if you name it explicitly on the command line, although currently you must
       also use the --skip-lock-tables option. Before MySQL 5.5 mysqldump silently ignores
       INFORMATION_SCHEMA even if you name it explicitly on the command line.

> tempDir = "/mnt/dumpspace"
> dumpUser = ""
> dumpUserPass = ""
> 
> if Dir["#{tempDir}/*"] != nil
>   puts "exits"

Typo? "exists" ?

>   FileUtils.rm_rf(Dir.glob("/mnt/dumpspace/*"))
> else
>   puts "doesn't exist, this should never be true!"
> end
> 
> date = Time.now.strftime("%m%e%g")
> puts date
> db = Mysql.real_connect('localhost',dumpUser,dumpUserPass)
> puts "Server version: " + db.get_server_info
> db.query('show databases').each do |db|
>   puts " Dumping - " + db[0] + "\n"
>   Dir.mkdir("#{tempDir}/#{db[0]}")
>   dump = "mysqldump -u #{dumpUser} -p#{dumpUserPass} #{db[0]} >
> #{tempDir}/#{db[0]}_#{date}.sql"
>   exec dump

`exec` will *replace* your running script and not return to it.

What you want here, is either backticks, system, or all the way to
something like Open3.capture2 or 3.

> end
> db.close

If you want a much more elegant solution to this and other backup
things, do look at the Backup gem:

https://github.com/meskyanichi/backup

Even if you don't use it, read it and learn from it. It's quite an
elegant bit of ruby code.