diff --git a/lua/platformio/pickers/init.lua b/lua/platformio/pickers/init.lua
index b9e6163..ef13ca9 100644
--- a/lua/platformio/pickers/init.lua
+++ b/lua/platformio/pickers/init.lua
@@ -3,61 +3,70 @@ local M = {}
 local config = require('platformio').config
 
 local function load_backend(name)
-  local ok, backend = pcall(require, 'platformio.pickers.' .. name)
-  if ok then
-    return backend
-  end
-  return nil
+    local ok, backend = pcall(require, 'platformio.pickers.' .. name)
+    if ok then
+        return backend
+    end
+    return nil
 end
 
 local function get_backend()
-  local backend_name = config.picker_backend or 'auto'
+    local backend_name = config.picker_backend or 'auto'
 
-  if backend_name == 'telescope' then
-    return load_backend('telescope') or load_backend('ui_select')
-  end
+    if backend_name == 'telescope' then
+        return load_backend('telescope') or load_backend('ui_select')
+    end
 
-  if backend_name == 'ui_select' then
-    return load_backend('ui_select')
-  end
+    if backend_name == 'ui_select' then
+        return load_backend('ui_select')
+    end
 
-  return load_backend('telescope') or load_backend('ui_select')
+    return load_backend('telescope') or load_backend('ui_select')
 end
 
 function M.pick_board(boards, on_select)
-  local backend = get_backend()
-  if not backend then
-    vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
-    return
-  end
-  backend.pick_board(boards, on_select)
+    local backend = get_backend()
+    if not backend then
+        vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
+        return
+    end
+    backend.pick_board(boards, on_select)
 end
 
 function M.pick_framework(frameworks, on_select)
-  local backend = get_backend()
-  if not backend then
-    vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
-    return
-  end
-  backend.pick_framework(frameworks, on_select)
+    local backend = get_backend()
+    if not backend then
+        vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
+        return
+    end
+    backend.pick_framework(frameworks, on_select)
 end
 
 function M.pick_library(libraries, on_select)
-  local backend = get_backend()
-  if not backend then
-    vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
-    return
-  end
-  backend.pick_library(libraries, on_select)
+    local backend = get_backend()
+    if not backend then
+        vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
+        return
+    end
+    backend.pick_library(libraries, on_select)
 end
 
 function M.pick_terminal(terminals, on_select)
-  local backend = get_backend()
-  if not backend then
-    vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
-    return
-  end
-  backend.pick_terminal(terminals, on_select)
+    local backend = get_backend()
+    if not backend then
+        vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
+        return
+    end
+    backend.pick_terminal(terminals, on_select)
+end
+
+function M.pick_env(envs, on_select)
+    local backend = get_backend()
+    if not backend then
+        vim.notify('No picker backend available for PlatformIO.', vim.log.levels.ERROR)
+        return
+    end
+    backend.pick_env(envs, on_select)
 end
 
 return M
diff --git a/lua/platformio/pickers/telescope.lua b/lua/platformio/pickers/telescope.lua
index d180099..8ab29e6 100644
--- a/lua/platformio/pickers/telescope.lua
+++ b/lua/platformio/pickers/telescope.lua
@@ -11,201 +11,224 @@ local previewers = require('telescope.previewers')
 local utils = require('platformio.utils')
 
 local function boardentry_maker(opts)
-  local displayer = entry_display.create({
-    separator = '▏',
-    items = {
-      { width = 35 },
-      { width = 20 },
-      { width = 15 },
-    },
-  })
-
-  local make_display = function(entry)
-    return displayer({
-      entry.value.name,
-      entry.value.vendor,
-      entry.value.platform,
+    local displayer = entry_display.create({
+        separator = '▏',
+        items = {
+            { width = 35 },
+            { width = 20 },
+            { width = 15 },
+        },
     })
-  end
 
-  return function(entry)
-    return make_entry.set_default_entry_mt({
-      value = {
-        id = entry.id,
-        name = entry.name,
-        vendor = entry.vendor,
-        platform = entry.platform,
-        data = entry,
-      },
-      ordinal = entry.name .. ' ' .. entry.vendor .. ' ' .. entry.platform,
-      display = make_display,
-    }, opts)
-  end
+    local make_display = function(entry)
+        return displayer({
+            entry.value.name,
+            entry.value.vendor,
+            entry.value.platform,
+        })
+    end
+
+    return function(entry)
+        return make_entry.set_default_entry_mt({
+            value = {
+                id = entry.id,
+                name = entry.name,
+                vendor = entry.vendor,
+                platform = entry.platform,
+                data = entry,
+            },
+            ordinal = entry.name .. ' ' .. entry.vendor .. ' ' .. entry.platform,
+            display = make_display,
+        }, opts)
+    end
 end
 
 local function libentry_maker(opts)
-  local displayer = entry_display.create({
-    separator = '▏',
-    items = {
-      { width = 20 },
-      { width = 20 },
-      { remaining = true },
-    },
-  })
-
-  local make_display = function(entry)
-    return displayer({
-      entry.value.name,
-      entry.value.owner,
-      entry.value.description,
+    local displayer = entry_display.create({
+        separator = '▏',
+        items = {
+            { width = 20 },
+            { width = 20 },
+            { remaining = true },
+        },
     })
-  end
 
-  return function(entry)
-    return make_entry.set_default_entry_mt({
-      value = {
-        name = entry.name,
-        owner = entry.owner and entry.owner.username or '',
-        description = entry.description,
-        data = entry,
-      },
-      ordinal = (entry.name or '') .. ' ' .. (entry.owner and entry.owner.username or '') .. ' ' .. (entry.description or ''),
-      display = make_display,
-    }, opts)
-  end
+    local make_display = function(entry)
+        return displayer({
+            entry.value.name,
+            entry.value.owner,
+            entry.value.description,
+        })
+    end
+
+    return function(entry)
+        return make_entry.set_default_entry_mt({
+            value = {
+                name = entry.name,
+                owner = entry.owner and entry.owner.username or '',
+                description = entry.description,
+                data = entry,
+            },
+            ordinal = (entry.name or '') .. ' ' .. (entry.owner and entry.owner.username or '') .. ' ' .. (entry.description or ''),
+            display = make_display,
+        }, opts)
+    end
 end
 
 function M.pick_framework(frameworks, on_select)
-  local opts = {}
-  pickers
-    .new(opts, {
-      prompt_title = 'frameworks',
-      finder = finders.new_table({
-        results = frameworks,
-      }),
-      attach_mappings = function(prompt_bufnr, _)
-        actions.select_default:replace(function()
-          actions.close(prompt_bufnr)
-          local selection = action_state.get_selected_entry()
-          if selection then
-            on_select(selection[1] or selection.value)
-          end
-        end)
-        return true
-      end,
-      sorter = telescope_conf.generic_sorter(opts),
-    })
-    :find()
+    local opts = {}
+    pickers
+        .new(opts, {
+            prompt_title = 'frameworks',
+            finder = finders.new_table({
+                results = frameworks,
+            }),
+            attach_mappings = function(prompt_bufnr, _)
+                actions.select_default:replace(function()
+                    actions.close(prompt_bufnr)
+                    local selection = action_state.get_selected_entry()
+                    if selection then
+                        on_select(selection[1] or selection.value)
+                    end
+                end)
+                return true
+            end,
+            sorter = telescope_conf.generic_sorter(opts),
+        })
+        :find()
 end
 
 function M.pick_board(boards, on_select)
-  local opts = {}
-  pickers
-    .new(opts, {
-      prompt_title = 'Boards',
-      finder = finders.new_table({
-        results = boards,
-        entry_maker = opts.entry_maker or boardentry_maker(opts),
-      }),
-      attach_mappings = function(prompt_bufnr, _)
-        actions.select_default:replace(function()
-          actions.close(prompt_bufnr)
-          local selection = action_state.get_selected_entry()
-          if selection and selection.value then
-            on_select(selection.value.data)
-          end
-        end)
-        return true
-      end,
-      previewer = previewers.new_buffer_previewer({
-        title = 'Board Info',
-        define_preview = function(self, entry, _)
-          local json = utils.strsplit(vim.inspect(entry.value.data), '\n')
-          local bufnr = self.state.bufnr
-          vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, json)
-          vim.api.nvim_set_option_value('filetype', 'lua', { buf = bufnr })
-          vim.defer_fn(function()
-            local win = self.state.winid
-            vim.api.nvim_set_option_value('wrap', true, { scope = 'local', win = win })
-            vim.api.nvim_set_option_value('linebreak', true, { scope = 'local', win = win })
-            vim.api.nvim_set_option_value('wrapmargin', 2, { buf = bufnr })
-          end, 0)
-        end,
-      }),
-      sorter = telescope_conf.generic_sorter(opts),
-    })
-    :find()
+    local opts = {}
+    pickers
+        .new(opts, {
+            prompt_title = 'Boards',
+            finder = finders.new_table({
+                results = boards,
+                entry_maker = opts.entry_maker or boardentry_maker(opts),
+            }),
+            attach_mappings = function(prompt_bufnr, _)
+                actions.select_default:replace(function()
+                    actions.close(prompt_bufnr)
+                    local selection = action_state.get_selected_entry()
+                    if selection and selection.value then
+                        on_select(selection.value.data)
+                    end
+                end)
+                return true
+            end,
+            previewer = previewers.new_buffer_previewer({
+                title = 'Board Info',
+                define_preview = function(self, entry, _)
+                    local json = utils.strsplit(vim.inspect(entry.value.data), '\n')
+                    local bufnr = self.state.bufnr
+                    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, json)
+                    vim.api.nvim_set_option_value('filetype', 'lua', { buf = bufnr })
+                    vim.defer_fn(function()
+                        local win = self.state.winid
+                        vim.api.nvim_set_option_value('wrap', true, { scope = 'local', win = win })
+                        vim.api.nvim_set_option_value('linebreak', true, { scope = 'local', win = win })
+                        vim.api.nvim_set_option_value('wrapmargin', 2, { buf = bufnr })
+                    end, 0)
+                end,
+            }),
+            sorter = telescope_conf.generic_sorter(opts),
+        })
+        :find()
 end
 
 function M.pick_library(libraries, on_select)
-  local opts = {}
-  pickers
-    .new(opts, {
-      prompt_title = 'Libraries',
-      finder = finders.new_table({
-        results = libraries,
-        entry_maker = opts.entry_maker or libentry_maker(opts),
-      }),
-      attach_mappings = function(prompt_bufnr, _)
-        actions.select_default:replace(function()
-          actions.close(prompt_bufnr)
-          local selection = action_state.get_selected_entry()
-          if selection and selection.value then
-            on_select(selection.value.data)
-          end
-        end)
-        return true
-      end,
-      previewer = previewers.new_buffer_previewer({
-        title = 'Package Info',
-        define_preview = function(self, entry, _)
-          local json = utils.strsplit(vim.inspect(entry.value.data), '\n')
-          local bufnr = self.state.bufnr
-          vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, json)
-          vim.api.nvim_set_option_value('filetype', 'lua', { buf = bufnr })
-          vim.defer_fn(function()
-            local win = self.state.winid
-            vim.api.nvim_set_option_value('wrap', true, { scope = 'local', win = win })
-            vim.api.nvim_set_option_value('linebreak', true, { scope = 'local', win = win })
-            vim.api.nvim_set_option_value('wrapmargin', 2, { buf = bufnr })
-          end, 0)
-        end,
-      }),
-      sorter = telescope_conf.generic_sorter(opts),
-    })
-    :find()
+    local opts = {}
+    pickers
+        .new(opts, {
+            prompt_title = 'Libraries',
+            finder = finders.new_table({
+                results = libraries,
+                entry_maker = opts.entry_maker or libentry_maker(opts),
+            }),
+            attach_mappings = function(prompt_bufnr, _)
+                actions.select_default:replace(function()
+                    actions.close(prompt_bufnr)
+                    local selection = action_state.get_selected_entry()
+                    if selection and selection.value then
+                        on_select(selection.value.data)
+                    end
+                end)
+                return true
+            end,
+            previewer = previewers.new_buffer_previewer({
+                title = 'Package Info',
+                define_preview = function(self, entry, _)
+                    local json = utils.strsplit(vim.inspect(entry.value.data), '\n')
+                    local bufnr = self.state.bufnr
+                    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, json)
+                    vim.api.nvim_set_option_value('filetype', 'lua', { buf = bufnr })
+                    vim.defer_fn(function()
+                        local win = self.state.winid
+                        vim.api.nvim_set_option_value('wrap', true, { scope = 'local', win = win })
+                        vim.api.nvim_set_option_value('linebreak', true, { scope = 'local', win = win })
+                        vim.api.nvim_set_option_value('wrapmargin', 2, { buf = bufnr })
+                    end, 0)
+                end,
+            }),
+            sorter = telescope_conf.generic_sorter(opts),
+        })
+        :find()
 end
 
 function M.pick_terminal(terminals, on_select)
-  local opts = {}
-  pickers
-    .new(opts, {
-      prompt_title = 'PIO terminals',
-      finder = finders.new_table({
-        results = terminals,
-        entry_maker = function(entry)
-          local is_hidden = vim.api.nvim_buf_is_loaded(entry.term.bufnr) and (vim.fn.bufwinid(entry.term.bufnr) == -1)
-          local label = string.format('%d:%s (hidden: %s)', entry.term.id, entry.termtype, tostring(is_hidden))
-          return {
-            value = entry,
-            display = label,
-            ordinal = label,
-          }
-        end,
-      }),
-      attach_mappings = function(prompt_bufnr, _)
-        actions.select_default:replace(function()
-          actions.close(prompt_bufnr)
-          local selection = action_state.get_selected_entry()
-          if selection and selection.value then
-            on_select(selection.value)
-          end
-        end)
-        return true
-      end,
-      sorter = telescope_conf.generic_sorter(opts),
-    })
-    :find()
+    local opts = {}
+    pickers
+        .new(opts, {
+            prompt_title = 'PIO terminals',
+            finder = finders.new_table({
+                results = terminals,
+                entry_maker = function(entry)
+                    local is_hidden = vim.api.nvim_buf_is_loaded(entry.term.bufnr) and (vim.fn.bufwinid(entry.term.bufnr) == -1)
+                    local label = string.format('%d:%s (hidden: %s)', entry.term.id, entry.termtype, tostring(is_hidden))
+                    return {
+                        value = entry,
+                        display = label,
+                        ordinal = label,
+                    }
+                end,
+            }),
+            attach_mappings = function(prompt_bufnr, _)
+                actions.select_default:replace(function()
+                    actions.close(prompt_bufnr)
+                    local selection = action_state.get_selected_entry()
+                    if selection and selection.value then
+                        on_select(selection.value)
+                    end
+                end)
+                return true
+            end,
+            sorter = telescope_conf.generic_sorter(opts),
+        })
+        :find()
+end
+
+function M.pick_env(envs, on_select)
+    local opts = {}
+    pickers
+        .new(opts, {
+            prompt_title = 'Environments',
+            finder = finders.new_table({
+                results = envs,
+            }),
+            attach_mappings = function(prompt_bufnr, _)
+                actions.select_default:replace(function()
+                    actions.close(prompt_bufnr)
+                    local selection = action_state.get_selected_entry()
+                    if selection and selection.value then
+                        on_select(selection.value)
+                    end
+                end)
+                return true
+            end,
+            sorter = telescope_conf.generic_sorter(opts),
+        })
+        :find()
 end
 
 return M
diff --git a/lua/platformio/pickers/ui_select.lua b/lua/platformio/pickers/ui_select.lua
index aa2ead8..0337a6f 100644
--- a/lua/platformio/pickers/ui_select.lua
+++ b/lua/platformio/pickers/ui_select.lua
@@ -1,62 +1,72 @@
 local M = {}
 
 local function board_label(board)
-  return string.format('%s | %s | %s', board.name or '', board.vendor or '', board.platform or '')
+    return string.format('%s | %s | %s', board.name or '', board.vendor or '', board.platform or '')
 end
 
 function M.pick_framework(frameworks, on_select)
-  vim.ui.select(frameworks, {
-    prompt = 'Select framework:',
-    format_item = function(item)
-      return item
-    end,
-  }, function(chosen)
-    if chosen then
-      on_select(chosen)
-    end
-  end)
+    vim.ui.select(frameworks, {
+        prompt = 'Select framework:',
+        format_item = function(item)
+            return item
+        end,
+    }, function(chosen)
+        if chosen then
+            on_select(chosen)
+        end
+    end)
 end
 
 function M.pick_board(boards, on_select)
-  vim.ui.select(boards, {
-    prompt = 'Select board:',
-    format_item = board_label,
-  }, function(chosen)
-    if chosen then
-      on_select(chosen)
-    end
-  end)
+    vim.ui.select(boards, {
+        prompt = 'Select board:',
+        format_item = board_label,
+    }, function(chosen)
+        if chosen then
+            on_select(chosen)
+        end
+    end)
 end
 
 function M.pick_library(libraries, on_select)
-  vim.ui.select(libraries, {
-    prompt = 'Select library:',
-    format_item = function(item)
-      local owner = (item.owner and item.owner.username) or ''
-      return string.format('%s | %s | %s', item.name or '', owner, item.description or '')
-    end,
-  }, function(chosen)
-    if chosen then
-      on_select(chosen)
-    end
-  end)
+    vim.ui.select(libraries, {
+        prompt = 'Select library:',
+        format_item = function(item)
+            local owner = (item.owner and item.owner.username) or ''
+            return string.format('%s | %s | %s', item.name or '', owner, item.description or '')
+        end,
+    }, function(chosen)
+        if chosen then
+            on_select(chosen)
+        end
+    end)
 end
 
 function M.pick_terminal(terminals, on_select)
-  vim.ui.select(terminals, {
-    prompt = 'Select a PIO terminal window:',
-    kind = 'PioTerminals',
-    format_item = function(item)
-      local is_hidden = vim.api.nvim_buf_is_loaded(item.term.bufnr) and (vim.fn.bufwinid(item.term.bufnr) == -1)
-      return string.format('%d:%s (hidden: %s)', item.term.id, item.termtype, tostring(is_hidden))
-    end,
-  }, function(chosen)
-    if chosen then
-      on_select(chosen)
-    else
-      on_select(nil)
-    end
-  end)
+    vim.ui.select(terminals, {
+        prompt = 'Select a PIO terminal window:',
+        kind = 'PioTerminals',
+        format_item = function(item)
+            local is_hidden = vim.api.nvim_buf_is_loaded(item.term.bufnr) and (vim.fn.bufwinid(item.term.bufnr) == -1)
+            return string.format('%d:%s (hidden: %s)', item.term.id, item.termtype, tostring(is_hidden))
+        end,
+    }, function(chosen)
+        if chosen then
+            on_select(chosen)
+        else
+            on_select(nil)
+        end
+    end)
+end
+
+function M.pick_env(envs, on_select)
+    vim.ui.select(envs, {
+        prompt = 'Select an environment to use as default:',
+    }, function(chosen)
+        if chosen then
+            on_select(chosen)
+        end
+    end)
 end
 
 return M
diff --git a/lua/platformio/piocmd.lua b/lua/platformio/piocmd.lua
index 0f5fde5..5450d8a 100644
--- a/lua/platformio/piocmd.lua
+++ b/lua/platformio/piocmd.lua
@@ -1,4 +1,5 @@
 local utils = require('platformio.utils')
+local env = require('platformio.pioenv')
 local M = {}
 
 function M.piocmd(cmd_table, direction)
@@ -15,6 +16,9 @@ function M.piocmd(cmd_table, direction)
     for _, v in pairs(cmd_table) do
       cmd = cmd .. ' ' .. v
     end
+    if env.command_accepts_flag(cmd_table[1]) then
+      cmd = cmd .. env.get_flag()
+    end
     utils.ToggleTerminal(cmd, direction)
   end
 end
diff --git a/lua/platformio/piodebug.lua b/lua/platformio/piodebug.lua
index d3786e5..67bb563 100644
--- a/lua/platformio/piodebug.lua
+++ b/lua/platformio/piodebug.lua
@@ -1,4 +1,5 @@
 local utils = require('platformio.utils')
+local env = require('platformio.pioenv')
 local M = {}
 
 function M.piodebug(args_table)
@@ -8,7 +9,7 @@ function M.piodebug(args_table)
 
   utils.cd_pioini()
 
-  local command = 'pio debug --interface=gdb -- -x .pioinit'
+  local command = 'pio debug --interface=gdb ' .. env.get_flag() .. ' -- -x .pioinit' -- utils.extra
   -- local command = string.format('pio debug --interface=gdb -- -x .pioinit %s', utils.extra)
   utils.ToggleTerminal(command, 'float')
 end
diff --git a/lua/platformio/pioenv.lua b/lua/platformio/pioenv.lua
new file mode 100644
index 0000000..7968193
--- /dev/null
+++ b/lua/platformio/pioenv.lua
@@ -0,0 +1,146 @@
+local utils = require('platformio.utils')
+local picker = require('platformio.pickers')
+local M = {
+  default_env = 'none',
+}
+local config = require('platformio').config
+
+--- changes symlink if feasible.
+function M.change_compiledb_symlink(env)
+  local pathsep = '/'
+  if utils.is_windows then
+    pathsep = '\\'
+  end
+  if M.default_env == 'none' then
+    vim.notify('compiledb does not exist for env ' .. M.default_env, vim.log.levels.ERROR, opts)
+    return
+  end
+  utils.cd_pioini()
+  local compile_commands_filename = 'compile_commands.json'
+  local compile_commands_path = '.pio' .. pathsep .. 'build' .. pathsep .. M.default_env .. pathsep .. compile_commands_filename
+  if not utils.file_exists(compile_commands_path) then
+    vim.notify(compile_commands_path .. ' does not exist to link it', vim.log.levels.ERROR, opts)
+    return
+  end
+  if utils.file_exists(compile_commands_filename) then
+    if not os.remove(compile_commands_filename) then
+      vim.notify(compile_commands_filename .. ' did not get removed', vim.log.levels.ERROR)
+      return
+    end
+  end
+  if config.clangd_source == 'compiledb' and utils.file_exists(compile_commands_path) then
+    if utils.is_windows then
+      os.execute('mklink ' .. compile_commands_filename .. ' ' .. compile_commands_path)
+    else
+      os.execute('ln -s ' .. compile_commands_path)
+    end
+  end
+end
+
+function M.pioenv()
+  --- @type vim.log.levels
+  local loglevel = vim.log.levels.INFO
+  utils.cd_pioini()
+
+  local cmd
+  -- TODO: execute target list command
+  if utils.is_windows then
+    cmd = 'pio run --list-targets'
+  else
+    cmd = 'grep -F "[env:" < platformio.ini | sed "s/\\[env://" | sed "s/\\]//"'
+  end
+  --- @type file*?
+  local stdio_stream
+  stdio_stream, _ = io.popen(cmd, 'r')
+  -- TODO: error checking
+  if not stdio_stream then
+    vim.notify('opening stdio or executing the cmd ' .. cmd .. 'failed', vim.log.levels.ERROR)
+    return
+  end
+
+  io.input(stdio_stream)
+  -- vim.notify(io.read('*a'), vim.log.levels.INFO)
+
+  -- table layout:
+  -- table header
+  -- ----------------------
+  -- env_name_without_spaces      some garbage
+  --
+  -- env_name_without_spaces      some garbage
+  -- ...
+
+  -- discard the first few lines, since they are just table headers and decorators
+  -- _ = stdio_stream.read(stdio_stream, '*l')
+  -- _ = stdio_stream.read(stdio_stream, '*l')
+
+  --- @type string[]
+  local envs = {}
+  --- @type integer | nil
+  local env_name_end
+  if utils.is_windows then
+    _ = stdio_stream.read(stdio_stream, '*line')
+    _ = stdio_stream.read(stdio_stream, '*line')
+  end
+  for line in stdio_stream.lines(stdio_stream, '*l') do -- readmode is for the output of lines as var `line`
+    if utils.is_windows then
+      env_name_end, _ = string.find(line, ' ', 2) -- if cmd succeeds, the env name has to be at least 1 char long and contains no spaces. skip the first one and search for space
+      env_name_end = env_name_end - 1
+      if env_name_end then -- would start at 1, regardless of start index, so we don't need to differentiate between 0 and nil
+        table.insert(envs, string.sub(line, 1, env_name_end))
+      else
+        vim.notify('formatting pio output failed on finding the first space char', vim.log.levels.ERROR)
+        io.close(stdio_stream)
+        return
+      end
+      _ = stdio_stream.read(stdio_stream, '*line')
+    else
+      table.insert(envs, line)
+    end
+  end
+
+  table.insert(envs, 'none')
+  io.close(stdio_stream)
+  -- TODO: execute picker
+  picker.pick_env(envs, function(selected_env)
+    M.default_env = selected_env
+    M.change_compiledb_symlink()
+  end)
+end
+
+--- function to use for other modules to get the env flag
+---@return string env_flag either an empty string, or a string with the flag
+function M.get_flag()
+  if M.default_env ~= 'none' then
+    return ' -e ' .. M.default_env
+  end
+  return ''
+end
+
+--- function to determine if a pio-command accepts the env flag
+---@param cmd string name of command that will be run
+---@return boolean accepts_flag is true if cmd accepts the env flag
+function M.command_accepts_flag(cmd)
+  local true_table = {
+    access = false,
+    account = false,
+    boards = false,
+    check = true,
+    ci = true,
+    debug = true,
+    device = false,
+    home = false,
+    org = false,
+    pkg = false,
+    project = false,
+    remote = false,
+    run = true,
+    setting = false,
+    system = false,
+    team = false,
+    test = true,
+    upgrade = false,
+  }
+  return true_table[cmd]
+end
+
+return M
diff --git a/lua/platformio/pioinit.lua b/lua/platformio/pioinit.lua
index 6cee0d3..2cbb0f9 100644
--- a/lua/platformio/pioinit.lua
+++ b/lua/platformio/pioinit.lua
@@ -36,21 +36,21 @@ function M.pioinit()
 
   -- Read stdout
   local command = 'pio boards --json-output'
-  local handel = io.popen(command .. utils.devNul)
-  if not handel then
+  local handle = io.popen(command .. utils.devNul)
+  if not handle then
     return
   end
-  local json_str = handel:read('*a')
-  handel:close()
+  local json_str = handle:read('*a')
+  handle:close()
 
   if #json_str == 0 then
     -- read stderr
-    handel = io.popen(command .. ' 2>&1')
-    if not handel then
+    handle = io.popen(command .. ' 2>&1')
+    if not handle then
       return
     end
-    local command_output = handel:read('*a')
-    handel:close()
+    local command_output = handle:read('*a')
+    handle:close()
     vim.notify('Some error occured while executing `' .. command .. "`', command output: \n", vim.log.levels.WARN)
     print(command_output)
     return
diff --git a/lua/platformio/piolsp.lua b/lua/platformio/piolsp.lua
index fac211e..f22ceb7 100644
--- a/lua/platformio/piolsp.lua
+++ b/lua/platformio/piolsp.lua
@@ -117,6 +117,7 @@ function M.piolsp()
     if config.lsp == 'clangd' then
       M.gen_clangd_config()
       gitignore_lsp_configs('compile_commands.json')
+      -- TODO: check for file first
       os.remove(vim.fs.joinpath(vim.g.platformioRootDir, '.ccls'))
     else
       gitignore_lsp_configs('.ccls')
diff --git a/lua/platformio/piorun.lua b/lua/platformio/piorun.lua
index 89020f2..5a39555 100644
--- a/lua/platformio/piorun.lua
+++ b/lua/platformio/piorun.lua
@@ -1,28 +1,29 @@
 local M = {}
 
 local utils = require('platformio.utils')
+local env = require('platformio.pioenv')
 
 function M.piobuild()
   utils.cd_pioini()
-  local command = 'pio run' -- .. utils.extra
+  local command = 'pio run' .. env.get_flag() -- .. utils.extra
   utils.ToggleTerminal(command, 'float')
 end
 
 function M.pioupload()
   utils.cd_pioini()
-  local command = 'pio run --target upload' -- .. utils.extra
+  local command = 'pio run --target upload' .. env.get_flag() -- .. utils.extra
   utils.ToggleTerminal(command, 'float')
 end
 
 function M.piouploadfs()
   utils.cd_pioini()
-  local command = 'pio run --target uploadfs' -- .. utils.extra
+  local command = 'pio run --target uploadfs' .. env.get_flag() -- .. utils.extra
   utils.ToggleTerminal(command, 'float')
 end
 
 function M.pioclean()
   utils.cd_pioini()
-  local command = 'pio run --target clean' -- .. utils.extra
+  local command = 'pio run --target clean' .. env.get_flag() -- .. utils.extra
   utils.ToggleTerminal(command, 'float')
 end
 
diff --git a/lua/platformio/utils.lua b/lua/platformio/utils.lua
index 83f8608..df15736 100644
--- a/lua/platformio/utils.lua
+++ b/lua/platformio/utils.lua
@@ -1,5 +1,10 @@
 local M = {}
 
+--- @alias userdir
+--- | '"data"'
+--- | '"state"'
+--- | '"cache"'
+
 local config = require('platformio').config
 
 -- M.extra = 'printf \'\\\\n\\\\033[0;33mPlease Press ENTER to continue \\\\033[0m\'; read'
@@ -24,14 +29,14 @@ local function pathmul(n)
 end
 
 ------------------------------------------------------
-local is_windows = jit.os == 'Windows'
+M.is_windows = jit.os == 'Windows'
 
-M.devNul = is_windows and ' 2>./nul' or ' 2>/dev/null'
+M.devNul = M.is_windows and ' 2>./nul' or ' 2>/dev/null'
 
 -- INFO: get current OS enter
 function M.enter()
   local shell = vim.o.shell
-  if is_windows then
+  if M.is_windows then
     return vim.fn.executable('pwsh') and '\r' or '\r\n'
   elseif shell:find('nu') then
     return '\r'
@@ -351,9 +356,9 @@ function M.cd_pioini()
 end
 
 function M.pio_install_check()
-  local handel = (jit.os == 'Windows') and assert(io.popen('where.exe pio 2>./nul')) or assert(io.popen('which pio 2>/dev/null'))
-  local pio_path = assert(handel:read('*a'))
-  handel:close()
+  local handle = (jit.os == 'Windows') and assert(io.popen('where.exe pio 2>./nul')) or assert(io.popen('which pio 2>/dev/null'))
+  local pio_path = assert(handle:read('*a'))
+  handle:close()
 
   if #pio_path == 0 then
     vim.notify('Platformio not found in the path', vim.log.levels.ERROR)
@@ -397,4 +402,31 @@ function M.shell_cmd_blocking(command)
   return result
 end
 
+--- gets the os user data dir for windows or linux
+---@return string data_dir_path
+function M.get_os_user_data_dir()
+  --- @type string
+  local os_dirname, path_separator
+  if M.is_windows then
+    path_separator = '\\'
+    os_dirname = 'LOCALAPPDATA'
+  else
+    path_separator = '/'
+    os_dirname = 'XDG_STATE_HOME'
+  end
+  return os.getenv(os_dirname) .. path_separator .. 'nvim' .. path_separator .. 'nvim-platformio'
+end
+
+--- creates the user data dir conditionally, based on its existence.
+---@return string data_dir_path for performance
+function M.make_os_user_data_dir()
+  local data_dir_path = M.get_os_user_data_dir()
+  local cmd = 'mkdir ' .. data_dir_path
+  if not M.is_windows then
+    cmd = cmd .. ' -p'
+  end
+  os.execute(cmd)
+  return data_dir_path
+end
+
 return M
diff --git a/plugin/platformio.lua b/plugin/platformio.lua
index 2373403..9c526bb 100644
--- a/plugin/platformio.lua
+++ b/plugin/platformio.lua
@@ -95,3 +95,7 @@ end, {})
 vim.api.nvim_create_user_command('PioTermList', function()
   require('platformio.piotermlist').piotermlist()
 end, {})
+
+vim.api.nvim_create_user_command('Pioenv', function()
+  require('platformio.pioenv').pioenv()
+end, {})