Ruby net-scp cannot scp multiple files with asterisk(*)

require 'net/scp'

host        = 'testmachine'
login       = 'testaccount'
password    = "testpassword"
remote_path = '/tmp/remote_dir/*'

Net::SCP.start(host, login, :password => password) do |scp|
  scp.download(remote_path, '.')
end

The root cause of this issue is actually being that * is escaped when the command is being built. Basically it's in the start_command method. When shellescape method is being called, * will be escaped. See below code in scp.rb.

str.gsub!(/([^A-Za-z0-9_\-.,:\/@\n])/n, "\\\\\\1")

Since * is escaped, the actual command being executed would look like

scp -f /tmp/remote_dir/\\*

This command will fail. Actually the issue should be resolved by updating the shellescape method to not escape *.

str.gsub!(/([^A-Za-z0-9_\-.,:\/@\n\*])/n, "\\\\\\1")

But before this issue can be actually fixed in the official gem, there are a few workarounds for this issue. The first one is to define your own shellescape method for the path which contains asterisk. Since the shellescape in scp.rb looks like

# Imported from ruby 1.9.2 shellwords.rb
def shellescape(path)
  # Convert path to a string if it isn't already one.
  str = path.to_s

  # ruby 1.8.7+ implements String#shellescape
  return str.shellescape if str.respond_to? :shellescape

  # An empty argument will be skipped, so return empty quotes.
  return "''" if str.empty?

  str = str.dup

  # Process as a single byte sequence because not all shell
  # implementations are multibyte aware.
  str.gsub!(/([^A-Za-z0-9_\-.,:\/@\n])/n, "\\\\\\1")

  # A LF cannot be escaped with a backslash because a backslash + LF
  # combo is regarded as line continuation and simply ignored.
  str.gsub!(/\n/, "'\n'")

  return str
end

Above code shows that if a str has shellescape defined, that method will be called and returned. So in your own script, you can do something

require 'net/scp'

host        = 'testmachine'
login       = 'testaccount'
password    = "testpassword"
remote_path = "/tmp/remote_dir/*"

def remote_path.shellescape
  p "In self defined method " + self.to_s
  self
end

Net::SCP.start(host, login, :password => password) do |scp|
  scp.download(remote_path, '.')
end

With this, multiple files can be downloaded.

Another alternative you can do is to download the whole directory if you want to download all files in a directory. The code would look like.

scp.download! "#{source_dir}", "#{target_dir}", :recursive => true

This method will create a directory in target_dir and download all files from source_dir to the newly created dir.