server 'example.com', roles: [:web, :app]
server 'example.org', roles: [:db, :workers]
desc "Report Uptimes"
task :uptime do
  on roles(:all) do |host|
    execute :any_command, "with args", :here, "and here"
    info "Host #{host} (#{host.roles.to_a.join(', ')}):\t#{capture(:uptime)}"


tl;dr: execute(:bundle, :install) and execute('bundle install') don’t behave identically!

execute() has a subtle behaviour. When calling within './directory' { execute(:bundle, :install) } for example, the first argument to execute() is a Stringish with no whitespace. This allows the command to pass through the SSHKit::CommandMap which enables a number of powerful features.

When the first argument to execute() contains whitespace, for example within './directory' { execute('bundle install') } (or when using a heredoc), neither Capistrano, nor SSHKit can reliably predict how it should be shell escaped, and thus cannot perform any context, or command mapping, that means that the within(){} (as well as with(), as(), etc) have no effect. There have been a few attempts to resolve this, but we don’t consider it a bug although we acknowledge that it might be a little counter intuitive.

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