diff --git a/CHANGELOG.md b/CHANGELOG.md
index 47046ca30..c4e90d34e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@ New features:
 - `spago run` now recognizes backend specified in the configuration file and calls the backend with `--run` argument.
 - documentation now includes a step-by-step guide on setting up a Spago/Parcel project (#456)
 - documentation now includes a step-by-step guide on setting up a Spago/Node and Spago/Webpack project (#456-extra)
+- moved warning and error logs to stderr, adjusted logging strategy (#256)
 - `spago path` returns output path so that it can be shared with tools such as `purs-loader`
 
 Bugfixes:
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 7e43a3e00..cb81002cb 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -83,6 +83,15 @@ $ npm install -g bower
 $ stack test
 ```
 
+note: if you receive the following error from running tests: 
+hGetContents: invalid argument (invalid byte sequence)
+
+You may be missing an environment variable. try the following
+
+```bash
+$ LC_ALL=en_US.iso88591 
+$ stack test
+```
 
 ## Merging changes
 
diff --git a/app/Curator.hs b/app/Curator.hs
index 8ef64ef6e..9a606cd04 100644
--- a/app/Curator.hs
+++ b/app/Curator.hs
@@ -117,11 +117,11 @@ main = do
   Env.setEnv "GIT_TERMINAL_PROMPT" "0"
 
   -- Read GitHub Auth Token
-  echo "Reading GitHub token.."
+  output "Reading GitHub token.."
   token <- (GitHub.OAuth . Encoding.encodeUtf8 . Text.pack) <$> Env.getEnv "SPACCHETTIBOTTI_TOKEN"
 
   -- Prepare data folder that will contain the temp copies of the repos
-  echo "Creating 'data' folder"
+  output "Creating 'data' folder"
   mktree "data"
 
   -- Start spawning threads
@@ -159,7 +159,7 @@ main = do
       let threadLoop = do
             pullChan <- atomically $ Chan.dupTChan bus
             forever $ atomically (Chan.readTChan pullChan) >>= thread
-      echo $ "Spawning thread " <> tshow name
+      output $ "Spawning thread " <> tshow name
       void $ Concurrent.forkIO $ catch threadLoop $ \(err :: SomeException) -> do
         -- TODO: use logError from RIO instead of this crap
         {-
@@ -171,7 +171,7 @@ main = do
           <> (BSL.fromStrict . Encoding.encodeUtf8 . tshow) err
           <> "\n\n\n"
         -}
-        echo $ "Thread " <> tshow name <> " broke, restarting.."
+        output $ "Thread " <> tshow name <> " broke, restarting.."
         spawnThread name thread
 
 
@@ -183,13 +183,13 @@ main = do
 
 getLatestRelease :: GitHub.AuthMethod am => am -> GitHubAddress -> IO (Either GitHub.Error GitHub.Release)
 getLatestRelease token address@(Address owner repo) = do
-  echo $ "Getting latest release for " <> tshow address
+  output $ "Getting latest release for " <> tshow address
   GitHub.executeRequest token $ GitHub.latestReleaseR owner repo
 
 
 getTags :: GitHub.AuthMethod am => am -> GitHubAddress -> IO (Either GitHub.Error (Maybe Tag, (Map Tag CommitHash)))
 getTags token address@(Address owner repo) = do
-  echo $ "Getting tags for " <> tshow address
+  output $ "Getting tags for " <> tshow address
   res <- GitHub.executeRequest token $ GitHub.tagsForR owner repo GitHub.FetchAll
   let f vec =
         ( (Tag . GitHub.tagName) <$> vec Vector.!? 0
@@ -206,7 +206,7 @@ getTags token address@(Address owner repo) = do
 
 getCommits :: GitHub.AuthMethod am => am -> GitHubAddress -> IO (Either GitHub.Error [CommitHash])
 getCommits token address@(Address owner repo) = do
-  echo $ "Getting commits for " <> tshow address
+  output $ "Getting commits for " <> tshow address
   res <- GitHub.executeRequest token $ GitHub.commitsForR owner repo GitHub.FetchAll
   pure $ fmap (Vector.toList . fmap (CommitHash . GitHub.untagName . GitHub.commitSha)) res
 
@@ -275,7 +275,7 @@ checkLatestRelease token address RefreshState = getLatestRelease token address >
       -- We don't do anything if we have a release saved and it's the current one
       Just currentRelease | currentRelease == releaseTagName -> pure ()
       _ -> do
-        echo $ "Found a new release for " <> tshow address <> ": " <> releaseTagName
+        output $ "Found a new release for " <> tshow address <> ": " <> releaseTagName
         atomically $ Chan.writeTChan bus $ NewRepoRelease address releaseTagName
 checkLatestRelease _ _ _ = pure ()
 
@@ -298,18 +298,18 @@ spagoUpdatePackageSets _ _ = pure ()
 --   the package on the bus.
 metadataFetcher :: GitHub.AuthMethod am => am -> Message -> IO ()
 metadataFetcher token RefreshState = do
-  echo "Downloading and parsing package set.."
+  output "Downloading and parsing package set.."
   packageSet <- fetchPackageSet
   atomically $ Chan.writeTChan bus $ NewPackageSet packageSet
   let packages = Map.toList packageSet
-  echoStr $ "Fetching metadata for " <> show (length packages) <> " packages"
+  outputStr $ "Fetching metadata for " <> show (length packages) <> " packages"
 
   -- Call GitHub for all these packages and get metadata for them
   metadata <- Async.withTaskGroup 10 $ \taskGroup -> do
     asyncs <- for packages (Async.async taskGroup . fetchRepoMetadata)
     for asyncs Async.wait
 
-  echo "Fetched all metadata."
+  output "Fetched all metadata."
   atomically $ Chan.writeTChan bus $ NewMetadata $ foldMap (uncurry Map.singleton) metadata
 
   where
@@ -325,7 +325,7 @@ metadataFetcher token RefreshState = do
                   False -> repoUrl
             address = Address (GitHub.mkName Proxy owner) (GitHub.mkName Proxy repo)
 
-        echo $ "Retry " <> tshow rsIterNumber <> ": fetching tags and commits for " <> tshow address
+        output $ "Retry " <> tshow rsIterNumber <> ": fetching tags and commits for " <> tshow address
 
         !eitherTags <- getTags token address
         !eitherCommits <- getCommits token address
@@ -356,9 +356,9 @@ metadataUpdater (NewMetadata metadata) = do
   let writeMetadata :: GHC.IO.FilePath -> IO ()
       writeMetadata tempfolder = do
         path <- makeAbsolute (tempfolder </> "metadataV1new.json")
-        echo $ "Writing metadata to file: " <> tshow path
+        output $ "Writing metadata to file: " <> tshow path
         BSL.writeFile path $ encodePretty metadata
-        echo "Done."
+        output "Done."
 
   let commitMessage = "Update GitHub index file"
   runAndPushMaster metadataRepo commitMessage
@@ -377,7 +377,7 @@ packageSetCommenter token (NewVerification result) = do
 
   case maybePR of
     Nothing -> do
-      echo "Could not find an open PR, waiting 5 mins.."
+      output "Could not find an open PR, waiting 5 mins.."
       Concurrent.threadDelay (5 * 60 * 1000000)
       atomically $ Chan.writeTChan bus $ NewVerification result
     Just GitHub.PullRequest{..} -> do
@@ -404,8 +404,8 @@ packageSetCommenter token (NewVerification result) = do
               ]
       let (Address owner repo) = packageSetsRepo
       (GitHub.executeRequest token $ GitHub.createCommentR owner repo pullRequestNumber commentBody) >>= \case
-        Left err -> echo $ "Something went wrong while commenting. Error: " <> tshow err
-        Right _ -> echo "Commented on the open PR"
+        Left err -> output $ "Something went wrong while commenting. Error: " <> tshow err
+        Right _ -> output "Commented on the open PR"
 packageSetCommenter _ _ = pure ()
 
 
@@ -458,13 +458,13 @@ packageSetsUpdater token (NewMetadata newMetadata) = do
 
   let patchVersions path = do
         for_ (Map.toList newVersionsWithBanned) $ \(packageName, (tag, owner)) -> do
-          echo $ "Patching version for " <> tshow packageName
+          output $ "Patching version for " <> tshow packageName
           withAST (Text.pack $ path </> "src" </> "groups" </> Text.unpack (Text.toLower owner) <> ".dhall")
             $ updateVersion packageName tag
 
-        echo "Verifying new set. This might take a LONG while.."
+        output "Verifying new set. This might take a LONG while.."
         result <- runWithCwd path "cd src; spago init; spago verify-set"
-        echo "Verified packages, spamming the channel with the result.."
+        output "Verified packages, spamming the channel with the result.."
         atomically $ Chan.writeTChan bus $ NewVerification result
 
   let commands =
@@ -473,10 +473,10 @@ packageSetsUpdater token (NewMetadata newMetadata) = do
         , "git add src/groups"
         ]
 
-  echo $ "Found " <> tshow (length newVersions) <> " packages to update"
+  output $ "Found " <> tshow (length newVersions) <> " packages to update"
 
   when (length newVersions > 0) $ do
-    echo $ tshow newVersions
+    output $ tshow newVersions
     -- If we have more than one package to update, let's see if we already have an
     -- open PR to package-sets. If we do we can just commit there
     maybePR <- getPullRequestForUser token "spacchettibotti" packageSetsRepo
@@ -514,7 +514,7 @@ packageSetsUpdater token (NewMetadata newMetadata) = do
                 , Time.diffUTCTime lastCommitTime lastCommentTime > 0
                 ]
         let patchVersions' path = shouldVerifyAgain path >>= \case
-              False -> echo "Skipping verification as there's nothing new under the sun.."
+              False -> output "Skipping verification as there's nothing new under the sun.."
               True -> do
                 patchVersions path
                 updatePullRequestBody token packageSetsRepo pullRequestNumber $ mkBody newVersions' newBanned
@@ -598,16 +598,16 @@ runAndOpenPR token PullRequest{ prAddress = address@Address{..}, ..} preAction c
   = unlessM pullRequestExists (runInClonedRepo address prBranchName prTitle preAction commands openPR)
   where
     openPR = do
-      echo "Pushed a new commit, opening PR.."
+      output "Pushed a new commit, opening PR.."
       response <- GitHub.executeRequest token
         $ GitHub.createPullRequestR owner repo
         $ GitHub.CreatePullRequest prTitle prBody prBranchName "master"
       case response of
-        Right _   -> echo "Created PR 🎉"
-        Left err' -> echoStr $ "Error while creating PR: " <> show err'
+        Right _   -> output "Created PR 🎉"
+        Left err' -> outputStr $ "Error while creating PR: " <> show err'
 
     pullRequestExists = do
-      echo $ "Checking if we ever opened a PR " <> surroundQuote prTitle
+      output $ "Checking if we ever opened a PR " <> surroundQuote prTitle
 
       oldPRs <- GitHub.executeRequest token
         $ GitHub.pullRequestsForR owner repo
@@ -615,13 +615,13 @@ runAndOpenPR token PullRequest{ prAddress = address@Address{..}, ..} preAction c
         GitHub.FetchAll
       case oldPRs of
         Left err -> do
-          echoStr $ "Error: " <> show err
+          outputStr $ "Error: " <> show err
           pure True
         Right prs | not $ Vector.null prs -> do
-          echo "PR was opened, skipping.."
+          output "PR was opened, skipping.."
           pure True
         Right _ -> do
-          echo "No previous PRs found, opening one.."
+          output "No previous PRs found, opening one.."
           pure False
 
 
@@ -635,28 +635,28 @@ runInClonedRepo address@Address{..} branchName commit preAction commands postAct
           if code /= ExitSuccess
             then do
               failure
-              echo out
-              echo err
+              output out
+              output err
             else success
 
     (code, _out, _err) <- runWithCwd path $ "git clone git@github.com:" <> GitHub.untagName owner <> "/" <> GitHub.untagName repo <> ".git"
     if code /= ExitSuccess
-      then echo "Error while cloning repo"
+      then output "Error while cloning repo"
       else do
-        echo $ "Cloned " <> tshow address
+        output $ "Cloned " <> tshow address
         -- Configure the repo: set the git identity to spacchettibotti and switch to the branch
         runInRepo
           [ "git config --local user.name 'Spacchettibotti'"
           , "git config --local user.email 'spacchettibotti@ferrai.io'"
           , "git checkout " <> branchName <> " || git checkout -b " <> branchName
           ]
-          (echo "Failed to configure the repo")
+          (output "Failed to configure the repo")
           -- If the setup was fine, run the setup code before running the commands
           (preAction =<< makeAbsolute (path </> repoPath))
         -- Run the commands we wanted to run
         runInRepo
           commands
-          (echo "Something was off while running commands..")
+          (output "Something was off while running commands..")
           -- Check if anything actually changed or got staged
           (runInRepo
             [ "git diff --staged --exit-code" ]
@@ -664,14 +664,14 @@ runInClonedRepo address@Address{..} branchName commit preAction commands postAct
               [ "git commit -m '" <> commit <> "'"
               , "git push --set-upstream origin " <> branchName
               ]
-              (echo "Failed to commit!")
+              (output "Failed to commit!")
               postAction)
-            (echo "Nothing to commit, skipping.."))
+            (output "Nothing to commit, skipping.."))
 
 
 runWithCwd :: MonadIO io => GHC.IO.FilePath -> Text -> io (ExitCode, Text, Text)
 runWithCwd cwd cmd = do
-  echo $ "Running in path " <> Text.pack cwd <> ": `" <> cmd <> "`"
+  output $ "Running in path " <> Text.pack cwd <> ": `" <> cmd <> "`"
   let processWithNewCwd = (Process.shell (Text.unpack cmd)) { Process.cwd = Just cwd }
   systemStrictWithErr processWithNewCwd empty
 
@@ -686,10 +686,10 @@ withAST :: MonadIO m => Text -> (Expr -> m Expr) -> m ()
 withAST path transform = do
   rawConfig <- liftIO $ Dhall.readRawExpr path
   case rawConfig of
-    Nothing -> echo $ "Could not find file " <> path
+    Nothing -> output $ "Could not find file " <> path
     Just (header, expr) -> do
       newExpr <- transformMExpr transform expr
-      echo $ "Done. Updating the \"" <> path <> "\" file.."
+      output $ "Done. Updating the \"" <> path <> "\" file.."
       writeTextFile path $ Dhall.prettyWithHeader header newExpr <> "\n"
       liftIO $ Dhall.format path
   where
diff --git a/src/Spago/Bower.hs b/src/Spago/Bower.hs
index 20c55e864..14139a189 100644
--- a/src/Spago/Bower.hs
+++ b/src/Spago/Bower.hs
@@ -47,7 +47,7 @@ runBower args = do
 
 generateBowerJson :: Spago m => m ByteString.ByteString
 generateBowerJson = do
-  echo "Generating a new Bower config using the package set versions.."
+  output "Generating a new Bower config using the package set versions.."
   config@Config{..} <- Config.ensureConfig
   PublishConfig{..} <- throws publishConfig
 
@@ -68,13 +68,13 @@ generateBowerJson = do
   when ignored $ do
     die $ path <> " is being ignored by git - change this before continuing"
 
-  echo "Generated a valid Bower config using the package set"
+  output "Generated a valid Bower config using the package set"
   pure bowerJson
 
 
 runBowerInstall :: Spago m => m ()
 runBowerInstall = do
-  echo "Running `bower install` so `pulp publish` can read resolved versions from it"
+  output "Running `bower install` so `pulp publish` can read resolved versions from it"
   shell "bower install --silent" empty >>= \case
     ExitSuccess   -> pure ()
     ExitFailure _ -> die "Failed to run `bower install` on your package"
diff --git a/src/Spago/Build.hs b/src/Spago/Build.hs
index 470e91613..918e44316 100644
--- a/src/Spago/Build.hs
+++ b/src/Spago/Build.hs
@@ -85,7 +85,7 @@ prepareBundleDefaults maybeModuleName maybeTargetPath = (moduleName, targetPath)
 --   eventually running some other action after the build
 build :: Spago m => BuildOptions -> Maybe (m ()) -> m ()
 build buildOpts@BuildOptions{..} maybePostBuild = do
-  echoDebug "Running `spago build`"
+  logDebug "Running `spago build`"
   config@Config.Config{ packageSet = Types.PackageSet{..}, ..} <- Config.ensureConfig
   deps <- Packages.getProjectDeps config
   case noInstall of
@@ -119,7 +119,7 @@ build buildOpts@BuildOptions{..} maybePostBuild = do
 
       case NonEmpty.nonEmpty (psMismatches <> jsMismatches) of
         Nothing -> pure ()
-        Just mismatches -> echo $ Messages.globsDoNotMatchWhenWatching $ NonEmpty.nub $ Text.pack <$> mismatches
+        Just mismatches -> output $ Messages.globsDoNotMatchWhenWatching $ NonEmpty.nub $ Text.pack <$> mismatches
 
       absolutePSGlobs <- traverse makeAbsolute psMatches
       absoluteJSGlobs <- traverse makeAbsolute jsMatches
@@ -154,7 +154,7 @@ repl
   -> Packages.DepsOnly
   -> m ()
 repl cacheFlag newPackages sourcePaths pursArgs depsOnly = do
-  echoDebug "Running `spago repl`"
+  logDebug "Running `spago repl`"
 
   try Config.ensureConfig >>= \case
     Right config@Config.Config{..} -> do
@@ -162,7 +162,7 @@ repl cacheFlag newPackages sourcePaths pursArgs depsOnly = do
       let globs = Packages.getGlobs deps depsOnly configSourcePaths <> sourcePaths
       Purs.repl globs pursArgs
     Left (err :: SomeException) -> do
-      echoDebug $ tshow err
+      logDebug $ tshow err
       cacheDir <- GlobalCache.getGlobalCacheDir
       Temp.withTempDirectory cacheDir "spago-repl-tmp" $ \dir -> do
         Turtle.cd (Turtle.decodeString dir)
@@ -207,7 +207,7 @@ runBackend
   -> [Purs.ExtraArg]
   -> m ()
 runBackend maybeBackend defaultModuleName maybeSuccessMessage failureMessage maybeModuleName buildOpts extraArgs = do
-  echoDebug $ "Running with backend: " <> fromMaybe "nodejs" maybeBackend
+  logDebug $ "Running with backend: " <> fromMaybe "nodejs" maybeBackend
   let postBuild = maybe (nodeAction =<< getOutputPath buildOpts) backendAction maybeBackend
   build buildOpts (Just postBuild)
   where
@@ -218,15 +218,15 @@ runBackend maybeBackend defaultModuleName maybeSuccessMessage failureMessage may
          in "#!/usr/bin/env node\n\n" <> "require('../" <> Text.pack path <> "/" <> Purs.unModuleName moduleName <> "').main()"
     nodeCmd = "node .spago/run.js " <> nodeArgs
     nodeAction outputPath' = do
-      echoDebug "Writing .spago/run.js"
+      logDebug "Writing .spago/run.js"
       writeTextFile ".spago/run.js" (nodeContents outputPath')
       chmod executable ".spago/run.js"
       shell nodeCmd empty >>= \case
-        ExitSuccess   -> maybe (pure ()) echo maybeSuccessMessage
+        ExitSuccess   -> maybe (pure ()) output maybeSuccessMessage
         ExitFailure n -> die $ failureMessage <> "exit code: " <> repr n
     backendAction backend =
       Turtle.proc backend (["--run" {-, Purs.unModuleName moduleName-}] <> fmap Purs.unExtraArg extraArgs) empty >>= \case
-        ExitSuccess   -> maybe (pure ()) echo maybeSuccessMessage
+        ExitSuccess   -> maybe (pure ()) output maybeSuccessMessage
         ExitFailure n -> die $ failureMessage <> "Backend " <> surroundQuote backend <> " exited with error:" <> repr n
 
   -- | Bundle the project to a js file
@@ -254,18 +254,18 @@ bundleModule
   -> BuildOptions
   -> m ()
 bundleModule maybeModuleName maybeTargetPath noBuild buildOpts = do
-  echoDebug "Running `bundleModule`"
+  logDebug "Running `bundleModule`"
   let (moduleName, targetPath) = prepareBundleDefaults maybeModuleName maybeTargetPath
       jsExport = Text.unpack $ "\nmodule.exports = PS[\""<> Purs.unModuleName moduleName <> "\"];"
       bundleAction = do
-        echo "Bundling first..."
+        output "Bundling first..."
         Purs.bundle Purs.WithoutMain moduleName targetPath
         -- Here we append the CommonJS export line at the end of the bundle
         try (with
               (appendonly $ pathFromText $ Purs.unTargetPath targetPath)
               (flip hPutStrLn jsExport))
           >>= \case
-            Right _ -> echo $ "Make module succeeded and output file to " <> Purs.unTargetPath targetPath
+            Right _ -> output $ "Make module succeeded and output file to " <> Purs.unTargetPath targetPath
             Left (n :: SomeException) -> die $ "Make module failed: " <> repr n
   case noBuild of
     DoBuild -> build buildOpts (Just bundleAction)
@@ -289,29 +289,29 @@ docs
   -> OpenDocs
   -> m ()
 docs format sourcePaths depsOnly noSearch open = do
-  echoDebug "Running `spago docs`"
+  logDebug "Running `spago docs`"
   config@Config.Config{..} <- Config.ensureConfig
   deps <- Packages.getProjectDeps config
-  echo "Generating documentation for the project. This might take a while..."
+  output "Generating documentation for the project. This might take a while..."
   Purs.docs docsFormat $ Packages.getGlobs deps depsOnly configSourcePaths <> sourcePaths
 
   when isHTMLFormat $ do
     when (noSearch == AddSearch) $ do
-      echo "Making the documentation searchable..."
+      output "Making the documentation searchable..."
       writeTextFile ".spago/purescript-docs-search" Templates.docsSearch
       writeTextFile ".spago/docs-search-app.js"     Templates.docsSearchApp
       let cmd = "node .spago/purescript-docs-search build-index"
-      echoDebug $ "Running `" <> cmd <> "`"
+      logDebug $ "Running `" <> cmd <> "`"
       shell cmd empty >>= \case
         ExitSuccess   -> pure ()
-        ExitFailure n -> echo $ "Failed while trying to make the documentation searchable: " <> repr n
+        ExitFailure n -> output $ "Failed while trying to make the documentation searchable: " <> repr n
 
     link <- linkToIndexHtml
     let linkText = "Link: " <> link
-    echo linkText
+    output linkText
 
     when (open == DoOpenDocs) $ do
-      echo "Opening in browser..."
+      output "Opening in browser..."
       () <$ openLink link
 
   where
@@ -330,7 +330,7 @@ search = do
   config@Config.Config{..} <- Config.ensureConfig
   deps <- Packages.getProjectDeps config
 
-  echo "Building module metadata..."
+  output "Building module metadata..."
 
   Purs.compile (Packages.getGlobs deps Packages.AllSources configSourcePaths)
     [ Purs.ExtraArg "--codegen"
@@ -339,7 +339,7 @@ search = do
 
   writeTextFile ".spago/purescript-docs-search" Templates.docsSearch
   let cmd = "node .spago/purescript-docs-search search"
-  echoDebug $ "Running `" <> cmd <> "`"
+  logDebug $ "Running `" <> cmd <> "`"
   viewShell $ callCommand $ Text.unpack cmd
 
 
@@ -376,7 +376,7 @@ showOutputPath
   => BuildOptions
   -> m ()
 showOutputPath buildOptions = 
-  echoStr =<< getOutputPathOrDefault buildOptions
+  outputStr =<< getOutputPathOrDefault buildOptions
 
 showPaths
   :: Spago m
@@ -396,7 +396,7 @@ showAllPaths buildOptions =
   traverse_ showPath =<< getAllPaths buildOptions
   where
     showPath (a,b) 
-      = echo (a <> ": " <> b)
+      = output (a <> ": " <> b)
 
 getAllPaths
   :: Spago m
@@ -440,7 +440,7 @@ getBuildArgsForSharedFolder buildOpts = do
         = Purs.ExtraArg . Text.pack . ("--output " <>)
   if any isOutputFlag pursArgs'
     then do
-      echo "Output path set explicitly - not using shared output path"
+      output "Output path set explicitly - not using shared output path"
       pure pursArgs'
     else do
       outputFolder <- getOutputPath buildOpts
diff --git a/src/Spago/Config.hs b/src/Spago/Config.hs
index 89ad52005..7ad5891eb 100644
--- a/src/Spago/Config.hs
+++ b/src/Spago/Config.hs
@@ -182,9 +182,9 @@ makeConfig force comments = do
       -- first, read the psc-package file content
       content <- readTextFile PscPackage.configPath
       case eitherDecodeStrict $ Text.encodeUtf8 content of
-        Left err -> echo $ Messages.failedToReadPscFile err
+        Left err -> output $ Messages.failedToReadPscFile err
         Right pscConfig -> do
-          echo "Found a \"psc-package.json\" file, migrating to a new Spago config.."
+          output "Found a \"psc-package.json\" file, migrating to a new Spago config.."
           -- try to update the dependencies (will fail if not found in package set)
           let pscPackages = map PackageSet.PackageName $ PscPackage.depends pscConfig
           config <- ensureConfig
@@ -196,7 +196,7 @@ makeConfig force comments = do
       case eitherDecodeStrict $ Text.encodeUtf8 content of
         Left err -> die $ Messages.failedToParseFile path err
         Right packageMeta -> do
-          echo "Found a \"bower.json\" file, migrating to a new Spago config.."
+          output "Found a \"bower.json\" file, migrating to a new Spago config.."
           -- then try to update the dependencies. We'll migrates the ones that we can,
           -- and print a message to the user to fix the missing ones
           config@Config{..} <- ensureConfig
@@ -206,10 +206,10 @@ makeConfig force comments = do
 
           if null bowerErrors
             then do
-              echo "All Bower dependencies are in the set! 🎉"
-              echo $ "You can now safely delete your " <> surroundQuote "bower.json"
+              output "All Bower dependencies are in the set! 🎉"
+              output $ "You can now safely delete your " <> surroundQuote "bower.json"
             else do
-              echo $ showBowerErrors bowerErrors
+              output $ showBowerErrors bowerErrors
 
           void $ withConfigAST (\e -> addRawDeps config bowerPackages
                                       $ updateName bowerName e)
@@ -297,7 +297,7 @@ addRawDeps config newPackages r@(Dhall.RecordLit kvs) = case Dhall.Map.lookup "d
                 $ Seq.sort $ nubSeq (Seq.fromList newPackages <> fmap PackageSet.PackageName oldPackages)
           pure $ Dhall.RecordLit $ Dhall.Map.insert "dependencies" newDepsExpr kvs
         Just pkgs -> do
-          echo $ Messages.failedToAddDeps $ NonEmpty.map PackageSet.packageName pkgs
+          output $ Messages.failedToAddDeps $ NonEmpty.map PackageSet.packageName pkgs
           pure r
     where
       packagesDB = PackageSet.packagesDB $ packageSet config
@@ -309,10 +309,10 @@ addRawDeps config newPackages r@(Dhall.RecordLit kvs) = case Dhall.Map.lookup "d
         where
           seens = Seq.scanl (flip Set.insert) Set.empty xs
   Just _ -> do
-    echo "WARNING: Failed to add dependencies. The `dependencies` field wasn't a List of Strings."
+    logWarning "Failed to add dependencies. The `dependencies` field wasn't a List of Strings."
     pure r
   Nothing -> do
-    echo "WARNING: Failed to add dependencies. You should have a record with the `dependencies` key for this to work."
+    logWarning "Failed to add dependencies. You should have a record with the `dependencies` key for this to work."
     pure r
 addRawDeps _ _ other = pure other
 
@@ -356,7 +356,7 @@ withConfigAST transform = do
       let exprHasChanged = Dhall.Core.denote expr /= newExpr
       if exprHasChanged
         then liftIO $ Dhall.writeRawExpr path (header, newExpr)
-        else echoDebug "Transformed config is the same as the read one, not overwriting it"
+        else logDebug "Transformed config is the same as the read one, not overwriting it"
       pure exprHasChanged
 
 
@@ -380,4 +380,4 @@ addDependencies :: Spago m => Config -> [PackageName] -> m ()
 addDependencies config newPackages = do
   configHasChanged <- withConfigAST $ addRawDeps config newPackages
   unless configHasChanged $
-    echo "WARNING: configuration file was not updated."
+    logWarning "configuration file was not updated."
diff --git a/src/Spago/DryRun.hs b/src/Spago/DryRun.hs
index e674f8171..a7f96e06c 100644
--- a/src/Spago/DryRun.hs
+++ b/src/Spago/DryRun.hs
@@ -19,10 +19,10 @@ data DryAction m
 
 runDryActions :: Spago m => DryRun -> NonEmpty (DryAction m) -> m ()
 runDryActions DryRun dryActions = do
-  echo "\nWARNING: this is a dry run, so these side effects were not performed:"
-  for_ dryActions $ \DryAction{..} -> echo $ "* " <> dryMessage
-  echo "\nUse the `--no-dry-run` flag to run them"
+  logWarning "this is a dry run, so these side effects were not performed:"
+  for_ dryActions $ \DryAction{..} -> output $ "* " <> dryMessage
+  output "\nUse the `--no-dry-run` flag to run them"
 runDryActions NoDryRun dryActions = do
   for_ dryActions $ \DryAction{..} -> do
-    echo $ "** Running action: " <> dryMessage
+    output $ "** Running action: " <> dryMessage
     dryAction
diff --git a/src/Spago/FetchPackage.hs b/src/Spago/FetchPackage.hs
index f2811f500..5f31e9fae 100644
--- a/src/Spago/FetchPackage.hs
+++ b/src/Spago/FetchPackage.hs
@@ -42,7 +42,7 @@ fetchPackages
   -> Maybe Version.SemVer
   -> m ()
 fetchPackages globalCacheFlag allDeps minPursVersion = do
-  echoDebug "Running `fetchPackages`"
+  logDebug "Running `fetchPackages`"
 
   PackageSet.checkPursIsUpToDate minPursVersion
 
@@ -60,7 +60,7 @@ fetchPackages globalCacheFlag allDeps minPursVersion = do
   -- Note: it might be empty depending on the cacheFlag
   let nOfDeps = List.length depsToFetch
   when (nOfDeps > 0) $ do
-    echoStr $ "Installing " <> show nOfDeps <> " dependencies."
+    outputStr $ "Installing " <> show nOfDeps <> " dependencies."
     metadata <- GlobalCache.getMetadata globalCacheFlag
 
     limit <- asks globalJobs
@@ -68,7 +68,7 @@ fetchPackages globalCacheFlag allDeps minPursVersion = do
       asyncs <- for depsToFetch (async' taskGroup . fetchPackage metadata)
       liftIO $ handle (handler asyncs) (for_ asyncs Async.wait)
 
-  echo "Installation complete."
+  output "Installation complete."
 
   where
     -- Here we have this weird exception handling so that threads can clean after
@@ -94,9 +94,9 @@ fetchPackages globalCacheFlag allDeps minPursVersion = do
 --   If it's a local directory do nothing
 fetchPackage :: Spago m => GlobalCache.ReposMetadataV1 -> (PackageName, Package) -> m ()
 fetchPackage _ (PackageName package, Package { location = Local{..}, .. }) =
-  echo $ Messages.foundLocalPackage package localPath
+  output $ Messages.foundLocalPackage package localPath
 fetchPackage metadata pair@(packageName'@PackageName{..}, Package{ location = Remote{..}, .. } ) = do
-  echoDebug $ "Fetching package " <> packageName
+  logDebug $ "Fetching package " <> packageName
   globalDir <- GlobalCache.getGlobalCacheDir
   let packageDir = getPackageDir packageName' version
       packageGlobalCacheDir = globalDir </> packageDir
@@ -110,7 +110,7 @@ fetchPackage metadata pair@(packageName'@PackageName{..}, Package{ location = Re
     -- * if a Package is in the global cache, copy it to the local cache
     if inGlobalCache
       then do
-        echo $ "Copying from global cache: " <> quotedName
+        output $ "Copying from global cache: " <> quotedName
         cptree packageGlobalCacheDir downloadDir
         assertDirectory (localCacheDir </> Text.unpack packageName)
         mv downloadDir packageLocalCacheDir
@@ -123,18 +123,18 @@ fetchPackage metadata pair@(packageName'@PackageName{..}, Package{ location = Re
               -- then atomically move it to the correct cache location.  Since
               -- `mv` will not move folders across filesystems, this temp
               -- is created inside globalDir, guaranteeing the same filesystem.
-              echo $ "Installing and globally caching " <> quotedName
+              output $ "Installing and globally caching " <> quotedName
               let resultDir2 = globalTemp </> "download2"
               assertDirectory resultDir2
               cptree resultDir resultDir2
               catch (mv resultDir2 packageGlobalCacheDir) $ \(err :: SomeException) ->
-                echoDebug $ Messages.failedToCopyToGlobalCache err
+                output $ Messages.failedToCopyToGlobalCache err
               mv resultDir packageLocalCacheDir
 
         -- * if not, run a series of git commands to get the code, and move it to local cache
         let nonCacheableCallback :: Spago m => m ()
             nonCacheableCallback = do
-              echo $ "Installing " <> quotedName
+              output $ "Installing " <> quotedName
 
               -- Here we set the package directory as the cwd of the new process.
               -- This is the "right" way to do it (instead of using e.g.
diff --git a/src/Spago/Git.hs b/src/Spago/Git.hs
index bd9d8900d..75fe9feae 100644
--- a/src/Spago/Git.hs
+++ b/src/Spago/Git.hs
@@ -24,7 +24,7 @@ hasCleanWorkingTree = do
   (code, stdout, stderr) <- Turtle.procStrictWithErr "git" ["status", "--porcelain"] empty
 
   when (code /= ExitSuccess) $ do
-    echoDebug $ "git status stderr: " <> stderr
+    logDebug $ "git status stderr: " <> stderr
     die "Unable to check git status. Perhaps git is not installed or this is not a git repository?"
 
   pure $ stdout == ""
diff --git a/src/Spago/GitHub.hs b/src/Spago/GitHub.hs
index 89d51313a..78269e595 100644
--- a/src/Spago/GitHub.hs
+++ b/src/Spago/GitHub.hs
@@ -28,9 +28,9 @@ login = do
  case maybeToken of
    Nothing -> die Messages.getNewGitHubToken
    Just (Text.pack -> token) -> do
-     echo "Token read, authenticating with GitHub.."
+     output "Token read, authenticating with GitHub.."
      username <- getUsername token
-     echo $ "Successfully authenticated as " <> surroundQuote username
+     output $ "Successfully authenticated as " <> surroundQuote username
      writeTextFile (Text.pack $ globalCacheDir </> tokenCacheFile) token
   where
     getUsername token = do
@@ -64,7 +64,7 @@ getLatestPackageSetsTag = do
   let readTagCache = try $ readTextFile $ pathFromText $ Text.pack globalPathToCachedTag
   let downloadTagToCache =
         try (Retry.recoverAll (Retry.fullJitterBackoff 50000 <> Retry.limitRetries 5) $ \_ -> getLatestRelease1 <|> getLatestRelease2) >>= \case
-          Left (err :: SomeException) -> echoDebug $ Messages.failedToReachGitHub err
+          Left (err :: SomeException) -> logDebug $ Messages.failedToReachGitHub err
           Right releaseTagName -> writeTagCache releaseTagName
 
   whenM (shouldRefreshFile globalPathToCachedTag) downloadTagToCache
@@ -78,14 +78,14 @@ getLatestPackageSetsTag = do
       f <- case hush maybeToken of
         Nothing -> pure GitHub.executeRequest'
         Just token -> do
-          echoDebug "Using cached GitHub token for getting the latest release.."
+          logDebug "Using cached GitHub token for getting the latest release.."
           pure $ GitHub.executeRequest (GitHub.OAuth $ Data.Text.Encoding.encodeUtf8 token)
       result <- liftIO $ f $ GitHub.latestReleaseR "purescript" "package-sets"
 
       case result of
         Right GitHub.Release{..} -> return releaseTagName
         Left err -> do
-          echo $ Messages.failedToReachGitHub err
+          logWarning $ Messages.failedToReachGitHub err
           empty
 
     -- | The idea here is that we go to the `latest` endpoint, and then get redirected
@@ -101,5 +101,5 @@ getLatestPackageSetsTag = do
       case Http.getResponseHeader "Location" response of
         [redirectUrl] -> return $ last $ Text.splitOn "/" $ Data.Text.Encoding.decodeUtf8 redirectUrl
         _ -> do
-          echoStr $ "Error following GitHub redirect, response:\n\n" <> show response
+          outputStr $ "Error following GitHub redirect, response:\n\n" <> show response
           empty
diff --git a/src/Spago/GlobalCache.hs b/src/Spago/GlobalCache.hs
index af478dd71..71eaee16f 100644
--- a/src/Spago/GlobalCache.hs
+++ b/src/Spago/GlobalCache.hs
@@ -52,7 +52,7 @@ globallyCache
   -> (m ())
   -> m ()
 globallyCache (packageName, Repo url, ref) downloadDir metadata cacheableCallback notCacheableCallback = do
-  echoDebug $ "Running `globallyCache`: " <> tshow packageName <> " " <> url <> " " <> ref
+  logDebug $ "Running `globallyCache`: " <> tshow packageName <> " " <> url <> " " <> ref
   case (Text.stripPrefix "https://github.com/" url)
        >>= (Text.stripSuffix ".git")
        >>= (Just . Text.split (== '/')) of
@@ -61,13 +61,13 @@ globallyCache (packageName, Repo url, ref) downloadDir metadata cacheableCallbac
         Nothing -> notCacheableCallback -- TODO: nice error?
         Just _ -> do
           let archiveUrl = "https://github.com/" <> owner <> "/" <> repo <> "/archive/" <> ref <> ".tar.gz"
-          echoDebug $ "About to fetch tarball for " <> archiveUrl
+          logDebug $ "About to fetch tarball for " <> archiveUrl
           fetchTarball downloadDir archiveUrl
           Just resultDir <- Turtle.fold (Turtle.ls $ Turtle.decodeString downloadDir) Fold.head
           cacheableCallback $ Turtle.encodeString resultDir
       where
     _ -> do
-      echo $ "WARNING: Not caching repo, because URL doesn't have the form of 'https://github.com/<ORG>/<REPO>.git': " <> url
+      logWarning $ "Not caching repo, because URL doesn't have the form of 'https://github.com/<ORG>/<REPO>.git': " <> url
       notCacheableCallback -- TODO: error?
   where
     isTag = do
@@ -85,11 +85,11 @@ globallyCache (packageName, Repo url, ref) downloadDir metadata cacheableCallbac
 -- | Download the GitHub Index cache from the `package-sets-metadata` repo
 getMetadata :: Spago m => Maybe CacheFlag -> m ReposMetadataV1
 getMetadata cacheFlag = do
-  echoDebug "Running `getMetadata`"
+  logDebug "Running `getMetadata`"
 
   globalCacheDir <- getGlobalCacheDir
 
-  echoDebug $ "Global cache directory: " <> Text.pack globalCacheDir
+  logDebug $ "Global cache directory: " <> Text.pack globalCacheDir
 
   let metaURL = "https://raw.githubusercontent.com/spacchetti/package-sets-metadata/master/metadataV1.json"
 
@@ -102,14 +102,14 @@ getMetadata cacheFlag = do
 
       downloadMeta = handleAny
         (\err -> do
-            echoDebug $ "Metadata fetch failed with exception: " <> tshow err
-            echo "WARNING: Unable to download GitHub metadata, global cache will be disabled"
+            logDebug $ "Metadata fetch failed with exception: " <> tshow err
+            output "WARNING: Unable to download GitHub metadata, global cache will be disabled"
             pure mempty)
         (do
             metaBS <- Http.getResponseBody `fmap` Http.httpBS metaURL
             case decodeStrict' metaBS of
               Nothing -> do
-                echo "WARNING: Unable to parse GitHub metadata, global cache will be disabled"
+                logWarning "Unable to parse GitHub metadata, global cache will be disabled"
                 pure mempty
               Just meta -> do
                 assertDirectory globalCacheDir
@@ -121,21 +121,21 @@ getMetadata cacheFlag = do
     Just SkipCache -> pure mempty
     -- If we need to download a new cache we can skip checking the local filesystem
     Just NewCache -> do
-      echo "Downloading a new packages cache metadata from GitHub.."
+      output "Downloading a new packages cache metadata from GitHub.."
       downloadMeta
     -- Otherwise we check first
     Nothing -> do
-      echo "Searching for packages cache metadata.."
+      output "Searching for packages cache metadata.."
 
       -- Check if the metadata is in global cache and fresher than 1 day
       shouldRefreshFile globalPathToMeta >>= \case
         -- If we should not download it, read from file
         False -> do
-          echo "Recent packages cache metadata found, using it.."
+          output "Recent packages cache metadata found, using it.."
           fmap maybeToMonoid $ liftIO $ decodeFileStrict globalPathToMeta
         -- Otherwise download it, write it to file, and return it
         True -> do
-          echo "Unable to find packages cache metadata, downloading from GitHub.."
+          output "Unable to find packages cache metadata, downloading from GitHub.."
           downloadMeta
 
 
@@ -146,14 +146,14 @@ getMetadata cacheFlag = do
 --   - (on Windows) the folder pointed by `LocalAppData`
 getGlobalCacheDir :: Spago m => m FilePath.FilePath
 getGlobalCacheDir = do
-  echoDebug "Running `getGlobalCacheDir`"
+  logDebug "Running `getGlobalCacheDir`"
   getXdgDirectory XdgCache "spago" <|> pure ".spago-global-cache"
 
 
 -- | Fetch the tarball at `archiveUrl` and unpack it into `destination`
 fetchTarball :: Spago m => FilePath.FilePath -> Text -> m ()
 fetchTarball destination archiveUrl = do
-  echoDebug $ "Fetching " <> archiveUrl
+  logDebug $ "Fetching " <> archiveUrl
   tarballUrl <- Http.parseRequest $ Text.unpack archiveUrl
   lbs <- fmap Http.getResponseBody (Http.httpLBS tarballUrl)
   liftIO $ Tar.unpack destination $ Tar.read $ GZip.decompress lbs
diff --git a/src/Spago/Messages.hs b/src/Spago/Messages.hs
index e265c1a42..4a91094e1 100644
--- a/src/Spago/Messages.hs
+++ b/src/Spago/Messages.hs
@@ -120,9 +120,9 @@ failedToParseFile file err = makeMessage
   ]
 
 failedToParseCommandOutput :: Text -> Text -> Text
-failedToParseCommandOutput command output = makeMessage
+failedToParseCommandOutput command outputText = makeMessage
   [ "Failed to parse '" <> command <> "' output: "
-  , surroundQuote output
+  , surroundQuote outputText
   ]
 
 failedToReachGitHub :: Show a => a -> Text
diff --git a/src/Spago/PackageSet.hs b/src/Spago/PackageSet.hs
index 2d1cdf89d..cbac65f39 100644
--- a/src/Spago/PackageSet.hs
+++ b/src/Spago/PackageSet.hs
@@ -35,7 +35,7 @@ makePackageSetFile force comments = do
   hasPackagesDhall <- testfile packagesPath
   if force || not hasPackagesDhall
     then writeTextFile packagesPath $ Dhall.processComments comments Templates.packagesDhall
-    else echo $ Messages.foundExistingProject packagesPath
+    else output $ Messages.foundExistingProject packagesPath
   Dhall.format packagesPath
 
 
@@ -48,19 +48,19 @@ makePackageSetFile force comments = do
 --   - if all of this succeeds, it will regenerate the hashes and write to file
 upgradePackageSet :: Spago m => m ()
 upgradePackageSet = do
-  echoDebug "Running `spago upgrade-set`"
+  logDebug "Running `spago upgrade-set`"
 
   GitHub.getLatestPackageSetsTag >>= \case
     Right tag -> updateTag tag
     Left (err :: SomeException) -> do
-      echo "WARNING: was not possible to upgrade the package-sets release"
-      echoDebug $ "Error: " <> tshow err
+      output "WARNING: was not possible to upgrade the package-sets release"
+      logDebug $ "Error: " <> tshow err
 
   where
     updateTag :: Spago m => Text -> m ()
     updateTag releaseTagName =  do
       let quotedTag = surroundQuote releaseTagName
-      echoDebug $ "Found the most recent tag for \"purescript/package-sets\": " <> quotedTag
+      logDebug $ "Found the most recent tag for \"purescript/package-sets\": " <> quotedTag
       rawPackageSet <- liftIO $ Dhall.readRawExpr packagesPath
       case rawPackageSet of
         Nothing -> die Messages.cannotFindPackages
@@ -68,11 +68,11 @@ upgradePackageSet = do
         Just (_, expr)
           | (currentTag:_) <- foldMap getCurrentTag expr
           , currentTag == releaseTagName
-            -> echo $ "Skipping package set version upgrade, already on latest version: " <> quotedTag
+            -> output $ "Skipping package set version upgrade, already on latest version: " <> quotedTag
         Just (header, expr) -> do
-          echo $ "Upgrading the package set version to " <> quotedTag
+          output $ "Upgrading the package set version to " <> quotedTag
           let newExpr = fmap (upgradeImports releaseTagName) expr
-          echo $ Messages.upgradingPackageSet releaseTagName
+          output $ Messages.upgradingPackageSet releaseTagName
           liftIO $ Dhall.writeRawExpr packagesPath (header, newExpr)
           -- If everything is fine, refreeze the imports
           freeze packagesPath
@@ -175,13 +175,13 @@ upgradePackageSet = do
 
 checkPursIsUpToDate :: Spago m => Maybe Version.SemVer -> m ()
 checkPursIsUpToDate packagesMinPursVersion = do
-  echoDebug "Checking if `purs` is up to date"
+  logDebug "Checking if `purs` is up to date"
   maybeCompilerVersion <- Purs.version
   case (maybeCompilerVersion, packagesMinPursVersion) of
     (Just compilerVersion, Just pursVersionFromPackageSet) -> performCheck compilerVersion pursVersionFromPackageSet
     other -> do
-      echo "WARNING: unable to parse compiler and package set versions, not checking if `purs` is compatible with it.."
-      echoDebug $ "Versions we got: " <> tshow other
+      logWarning "unable to parse compiler and package set versions, not checking if `purs` is compatible with it.."
+      logDebug $ "Versions we got: " <> tshow other
   where
     -- | The check is successful only when the installed compiler is "slightly"
     --   greater (or equal of course) to the minimum version. E.g. fine cases are:
@@ -237,7 +237,7 @@ rootPackagePath _ = Nothing
 -- | so we build into an output folder where our root packages.dhall lives
 findRootOutputPath :: Spago m => System.IO.FilePath -> m (Maybe System.IO.FilePath)
 findRootOutputPath path = do
-  echoDebug "Locating root path of packages.dhall"
+  logDebug "Locating root path of packages.dhall"
   imports <- liftIO $ Dhall.readImports $ Text.pack path
   let localImports = mapMaybe rootPackagePath imports
   pure $ flip System.FilePath.replaceFileName "output" <$> findRootPath localImports
@@ -249,7 +249,7 @@ findRootPath = Safe.minimumByMay (comparing (length . System.FilePath.splitSearc
 -- | Freeze the package set remote imports so they will be cached
 freeze :: Spago m => System.IO.FilePath -> m ()
 freeze path = do
-  echo Messages.freezePackageSet
+  output Messages.freezePackageSet
   liftIO $
     Dhall.Freeze.freeze
       (Dhall.InputFile path)
@@ -262,10 +262,10 @@ freeze path = do
 -- | Freeze the file if any of the remote imports are not frozen
 ensureFrozen :: Spago m => System.IO.FilePath -> m ()
 ensureFrozen path = do
-  echoDebug "Ensuring that the package set is frozen"
+  logDebug "Ensuring that the package set is frozen"
   imports <- liftIO $ Dhall.readImports $ Text.pack path
   let areRemotesFrozen = foldMap isRemoteFrozen imports
   case areRemotesFrozen of
-    []      -> echo Messages.failedToCheckPackageSetFrozen
+    []      -> output Messages.failedToCheckPackageSetFrozen
     remotes -> unless (and remotes) $
       traverse_ (maybe (pure ()) freeze . localImportPath) imports
diff --git a/src/Spago/Packages.hs b/src/Spago/Packages.hs
index 7a8c843bb..4ea9dc94a 100644
--- a/src/Spago/Packages.hs
+++ b/src/Spago/Packages.hs
@@ -48,7 +48,7 @@ import           Spago.Types              as PackageSet
 --   - create an example `test` folder (if needed)
 initProject :: Spago m => Bool -> Dhall.TemplateComments -> m ()
 initProject force comments = do
-  echo "Initializing a sample project or migrating an existing one.."
+  output "Initializing a sample project or migrating an existing one.."
 
   -- packages.dhall and spago.dhall overwrite can be forced
   PackageSet.makePackageSetFile force comments
@@ -68,22 +68,22 @@ initProject force comments = do
 
   copyIfNotExists ".gitignore" Templates.gitignore
 
-  echo "Set up a local Spago project."
-  echo "Try running `spago build`"
+  output "Set up a local Spago project."
+  output "Try running `spago build`"
 
   where
     whenDirNotExists dir action = do
       let dirPath = pathFromText dir
       dirExists <- testdir dirPath
       case dirExists of
-        True -> echo $ Messages.foundExistingDirectory dir
+        True -> output $ Messages.foundExistingDirectory dir
         False -> do
           mktree dirPath
           action
 
     copyIfNotExists dest srcTemplate = do
       testfile dest >>= \case
-        True  -> echo $ Messages.foundExistingFile dest
+        True  -> output $ Messages.foundExistingFile dest
         False -> writeTextFile dest srcTemplate
 
 
@@ -131,7 +131,7 @@ getProjectDeps Config{..} = getTransitiveDeps packageSet dependencies
 -- | Return the transitive dependencies of a list of packages
 getTransitiveDeps :: Spago m => PackageSet -> [PackageName] -> m [(PackageName, Package)]
 getTransitiveDeps PackageSet{..} deps = do
-  echoDebug "Getting transitive deps"
+  logDebug "Getting transitive deps"
   let (packageMap, notFoundErrors, cycleErrors) = State.evalState (fold <$> traverse (go mempty) deps) mempty
 
   handleErrors (Map.toList packageMap) (Set.toList notFoundErrors) (Set.toList cycleErrors)
@@ -193,7 +193,7 @@ getReverseDeps packageSet@PackageSet{..} dep = do
 -- | Fetch all dependencies into `.spago/`
 install :: Spago m => Maybe CacheFlag -> [PackageName] -> m ()
 install cacheFlag newPackages = do
-  echoDebug "Running `spago install`"
+  logDebug "Running `spago install`"
   config@Config{ packageSet = PackageSet{..}, ..} <- Config.ensureConfig
 
   existingNewPackages <- reportMissingPackages $ classifyPackages packagesDB newPackages
@@ -218,7 +218,7 @@ reportMissingPackages (PackagesLookupResult found foundWithoutPrefix notFound) =
         <> (Text.intercalate "\n" . fmap (\(NotFoundError p) -> "  - " <> packageName p) $ List.sort notFound)
 
   for_ foundWithoutPrefix $ \(FoundWithoutPrefix sansPrefix) ->
-    echo $ "WARNING: the package 'purescript-" <> packageName sansPrefix <> "' was not found in your package set, but '"
+    output $ "WARNING: the package 'purescript-" <> packageName sansPrefix <> "' was not found in your package set, but '"
          <> packageName sansPrefix <> "' was. Using that instead."
   pure found
 
@@ -269,7 +269,7 @@ encodeJsonPackageOutput = LT.toStrict . LT.decodeUtf8 . Aeson.encode
 -- | A list of the packages that can be added to this project
 listPackages :: Spago m => Maybe PackagesFilter -> JsonFlag -> m ()
 listPackages packagesFilter jsonFlag = do
-  echoDebug "Running `listPackages`"
+  logDebug "Running `listPackages`"
   Config{packageSet = packageSet@PackageSet{..}, ..} <- Config.ensureConfig
   packagesToList :: [(PackageName, Package)] <- case packagesFilter of
     Nothing             -> pure $ Map.toList packagesDB
@@ -278,8 +278,8 @@ listPackages packagesFilter jsonFlag = do
       $ Map.restrictKeys packagesDB (Set.fromList dependencies)
 
   case packagesToList of
-    [] -> echo "There are no dependencies listed in your spago.dhall"
-    _  -> traverse_ echo $ formatPackageNames packagesToList
+    [] -> output "There are no dependencies listed in your spago.dhall"
+    _  -> traverse_ output $ formatPackageNames packagesToList
 
   where
     formatPackageNames = case jsonFlag of
@@ -332,10 +332,10 @@ listPackages packagesFilter jsonFlag = do
 -- | Get source globs of dependencies listed in `spago.dhall`
 sources :: Spago m => m ()
 sources = do
-  echoDebug "Running `spago sources`"
+  logDebug "Running `spago sources`"
   config <- Config.ensureConfig
   deps <- getProjectDeps config
-  traverse_ echo
+  traverse_ output
     $ fmap Purs.unSourcePath
     $ getGlobs deps AllSources
     $ Config.configSourcePaths config
@@ -345,7 +345,7 @@ data CheckModulesUnique = DoCheckModulesUnique | NoCheckModulesUnique
 
 verify :: Spago m => Maybe CacheFlag -> CheckModulesUnique -> Maybe PackageName -> m ()
 verify cacheFlag chkModsUniq maybePackage = do
-  echoDebug "Running `spago verify`"
+  logDebug "Running `spago verify`"
   Config{ packageSet = packageSet@PackageSet{..}, ..} <- Config.ensureConfig
   case maybePackage of
     -- If no package is specified, verify all of them
@@ -369,7 +369,7 @@ verify cacheFlag chkModsUniq maybePackage = do
   where
     verifyPackages :: Spago m => PackageSet -> [(PackageName, Package)] -> m ()
     verifyPackages packageSet packages = do
-      echo $ Messages.verifying $ length packages
+      output $ Messages.verifying $ length packages
       traverse_ (verifyPackage packageSet) (fst <$> packages)
 
     verifyPackage :: Spago m => PackageSet -> PackageName -> m ()
@@ -378,15 +378,15 @@ verify cacheFlag chkModsUniq maybePackage = do
       let globs = getGlobs deps DepsOnly []
           quotedName = surroundQuote $ packageName name
       Fetch.fetchPackages cacheFlag deps packagesMinPursVersion
-      echo $ "Verifying package " <> quotedName
+      output $ "Verifying package " <> quotedName
       Purs.compile globs []
-      echo $ "Successfully verified " <> quotedName
+      output $ "Successfully verified " <> quotedName
 
     compileEverything :: Spago m => PackageSet -> m ()
     compileEverything PackageSet{..} = do
       let deps = Map.toList packagesDB
           globs = getGlobs deps DepsOnly []
       Fetch.fetchPackages cacheFlag deps packagesMinPursVersion
-      echo "Compiling everything (will fail if module names conflict)"
+      output "Compiling everything (will fail if module names conflict)"
       Purs.compile globs []
-      echo "Successfully compiled everything"
+      output "Successfully compiled everything"
diff --git a/src/Spago/Prelude.hs b/src/Spago/Prelude.hs
index 317bd54c8..a151cabb9 100644
--- a/src/Spago/Prelude.hs
+++ b/src/Spago/Prelude.hs
@@ -1,8 +1,5 @@
 module Spago.Prelude
-  ( echo
-  , echoStr
-  , echoDebug
-  , tshow
+  ( tshow
   , die
   , Dhall.Core.throws
   , hush
@@ -83,6 +80,11 @@ module Spago.Prelude
   , whenM
   , unlessM
   , pretty
+  , output
+  , outputStr
+  , logDebug
+  , logWarning
+  , logError
   ) where
 
 
@@ -164,25 +166,36 @@ type Spago m =
   , MonadMask m
   )
 
-echo :: MonadIO m => Text -> m ()
-echo = Turtle.printf (Turtle.s Turtle.% "\n")
+output :: MonadIO m => Text -> m ()
+output = Turtle.printf (Turtle.s Turtle.% "\n")
 
-echoStr :: MonadIO m => String -> m ()
-echoStr = echo . Text.pack
+outputStr :: MonadIO m => String -> m ()
+outputStr = output . Text.pack
 
-tshow :: Show a => a -> Text
-tshow = Text.pack . show
+logStderr :: MonadIO m => String -> m () 
+logStderr = liftIO . System.IO.hPutStrLn System.IO.stderr
+
+logText :: MonadIO m => Text -> m ()
+logText = logStderr . Text.unpack
 
-echoDebug :: Spago m => Text -> m ()
-echoDebug str = do
+logDebug :: Spago m => Text -> m ()
+logDebug str = do
   hasDebug <- asks globalDebug
-  Turtle.when hasDebug $ do
-    echo str
+  when hasDebug $ do
+    logText $ str
+
+logWarning :: MonadIO m => Text -> m ()
+logWarning = logText . ("WARNING: " <>)
+
+logError :: MonadIO m => Text -> m ()
+logError = logText . ("ERROR: " <>)
+
+tshow :: Show a => a -> Text
+tshow = Text.pack . show
 
 die :: MonadThrow m => Text -> m a
 die reason = throwM $ SpagoError reason
 
-
 -- | Suppress the 'Left' value of an 'Either'
 hush :: Either a b -> Maybe b
 hush = either (const Nothing) Just
@@ -290,7 +303,7 @@ shouldRefreshFile path = (tryIO $ liftIO $ do
   >>= \case
   Right v -> pure v
   Left err -> do
-    echoDebug $ "Unable to read file " <> Text.pack path <> ". Error was: " <> tshow err
+    logDebug $ "Unable to read file " <> Text.pack path <> ". Error was: " <> tshow err
     pure True
 
 
diff --git a/src/Spago/Purs.hs b/src/Spago/Purs.hs
index ab614cf82..1ffb49b01 100644
--- a/src/Spago/Purs.hs
+++ b/src/Spago/Purs.hs
@@ -42,7 +42,7 @@ compile sourcePaths extraArgs = do
       Right _ -> pure "psa"
       Left (_err :: SomeException) -> pure "purs"
 
-  echoDebug $ "Compiling with " <> surroundQuote purs
+  logDebug $ "Compiling with " <> surroundQuote purs
 
   let
     paths = Text.intercalate " " $ surroundQuote <$> map unSourcePath sourcePaths
@@ -124,14 +124,14 @@ versionImpl purs = do
       parsed = versionText >>= (hush . Version.semver)
 
   when (isNothing parsed) $ do
-    echo $ Messages.failedToParseCommandOutput (purs <> " --version") fullVersionText
+    output $ Messages.failedToParseCommandOutput (purs <> " --version") fullVersionText
 
   pure parsed
 
 
 runWithOutput :: Spago m => Text -> Text -> Text -> m ()
 runWithOutput command success failure = do
-  echoDebug $ "Running command: `" <> command <> "`"
+  logDebug $ "Running command: `" <> command <> "`"
   liftIO $ shell command empty >>= \case
-    ExitSuccess -> echo success
+    ExitSuccess -> output success
     ExitFailure _ -> die failure
diff --git a/src/Spago/Version.hs b/src/Spago/Version.hs
index db3600c48..dad88edee 100644
--- a/src/Spago/Version.hs
+++ b/src/Spago/Version.hs
@@ -59,10 +59,10 @@ getCurrentVersion = do
 
   case Safe.maximumMay tags of
     Nothing -> do
-      echo $ "No git version tags found, so assuming current version is " <> unparseVersion mempty
+      output $ "No git version tags found, so assuming current version is " <> unparseVersion mempty
       pure mempty
     Just maxVersion -> do
-      echo $ "Found current version from git tag: " <> unparseVersion maxVersion
+      output $ "Found current version from git tag: " <> unparseVersion maxVersion
       pure maxVersion
 
 
@@ -88,7 +88,7 @@ tagNewVersion oldVersion newVersion = do
       newVersionTag = unparseVersion newVersion
 
   Git.commitAndTag newVersionTag $ oldVersionTag <> " → " <> newVersionTag
-  echo $ "Git tag created for new version: " <> newVersionTag
+  output $ "Git tag created for new version: " <> newVersionTag
 
 
 -- | Bump and tag a new version in preparation for release.
@@ -103,7 +103,7 @@ bumpVersion dryRun spec = do
 
   let writeBowerAction = DryAction
         "write the new config to the `bower.json` file and try to install its dependencies" $ do
-        echo $ "Writing the new Bower config to " <> surroundQuote Bower.path
+        output $ "Writing the new Bower config to " <> surroundQuote Bower.path
         liftIO $ ByteString.writeFile Bower.path newBowerConfig
         Bower.runBowerInstall
         clean <- Git.hasCleanWorkingTree
diff --git a/src/Spago/Watch.hs b/src/Spago/Watch.hs
index 53e65c055..26bf8b321 100644
--- a/src/Spago/Watch.hs
+++ b/src/Spago/Watch.hs
@@ -68,7 +68,7 @@ fileWatchConf watchConfig shouldClear inner = withManagerConf watchConfig $ \man
           when (shouldClear == DoClear) $ liftIO $ do
             clearScreen
             setCursorPosition 0 0
-          mapM_ echoStr maybeMsg
+          mapM_ outputStr maybeMsg
 
     let onChange event = do
           timeNow <- liftIO getCurrentTime
@@ -136,25 +136,25 @@ fileWatchConf watchConfig shouldClear inner = withManagerConf watchConfig $ \man
     let watchInput :: Spago m => m ()
         watchInput = do
           line <- liftIO $ unpack . toLower . pack <$> getLine
-          if line == "quit" then echo "Leaving watch mode."
+          if line == "quit" then output "Leaving watch mode."
           else do
             liftIO $ case line of
               "help" -> do
-                echo ""
-                echo "help: display this help"
-                echo "quit: exit"
-                echo "build: force a rebuild"
-                echo "watched: display watched files"
+                output ""
+                output "help: display this help"
+                output "quit: exit"
+                output "build: force a rebuild"
+                output "watched: display watched files"
               "build" -> do
                 redisplay Nothing
                 atomically $ writeTVar dirtyVar True
               "watched" -> do
                 watch' <- readTVarIO allGlobs
-                mapM_ echoStr (Glob.decompile <$> Set.toList watch')
+                mapM_ outputStr (Glob.decompile <$> Set.toList watch')
               "" -> do
                 redisplay Nothing
                 atomically $ writeTVar dirtyVar True
-              _ -> echoStr $ concat
+              _ -> outputStr $ concat
                   [ "Unknown command: "
                   , show line
                   , ". Try 'help'"
@@ -170,10 +170,10 @@ fileWatchConf watchConfig shouldClear inner = withManagerConf watchConfig $ \man
       eres :: Either SomeException () <- try $ inner setWatched
 
       case eres of
-        Left e -> echoStr $ show e
-        _      -> echo "Success! Waiting for next file change."
+        Left e -> outputStr $ show e
+        _      -> output "Success! Waiting for next file change."
 
-      echo "Type help for available commands. Press enter to force a rebuild."
+      output "Type help for available commands. Press enter to force a rebuild."
 
 
 globToParent :: Glob.Pattern -> FilePath
diff --git a/test/SpagoSpec.hs b/test/SpagoSpec.hs
index b2b38ac33..cdb49d9f5 100644
--- a/test/SpagoSpec.hs
+++ b/test/SpagoSpec.hs
@@ -9,9 +9,11 @@ import           Test.Hspec         (Spec, around_, describe, it, shouldBe, shou
 import           Turtle             (ExitCode (..), cd, cp, decodeString, empty, mkdir, mktree, mv,
                                      readTextFile, rm, shell, shellStrictWithErr, testdir,
                                      writeTextFile)
-import           Utils              (checkFileHasInfix, checkFixture, outputShouldEqual,
-                                     readFixture, runFor, shouldBeFailure, shouldBeFailureOutput,
-                                     shouldBeSuccess, shouldBeSuccessOutput, spago, withCwd)
+import           Utils              (checkFileHasInfix, checkFixture, readFixture, runFor,
+                                     shouldBeFailure, shouldBeFailureOutput, shouldBeSuccess,
+                                     shouldBeSuccessOutput, shouldBeSuccessOutputWithErr, spago, withCwd,
+                                     outputShouldEqual)
+
 
 
 setup :: IO () -> IO ()
@@ -95,7 +97,7 @@ spec = around_ setup $ do
 
       spago ["init"] >>= shouldBeSuccess
       spago ["install"] >>= shouldBeSuccess
-      spago ["install", "effect"] >>= shouldBeSuccessOutput "spago-install-existing-dep-warning.txt"
+      spago ["install", "effect"] >>= shouldBeSuccessOutputWithErr "spago-install-existing-dep-output.txt" "spago-install-existing-dep-warning.txt"
 
     it "Spago should strip 'purescript-' prefix and give warning if package without prefix is present in package set" $ do
 
@@ -168,7 +170,7 @@ spec = around_ setup $ do
       spago ["init"] >>= shouldBeSuccess
       writeTextFile "alternative2.dhall" "./spago.dhall // { sources = [ \"src/**/*.purs\" ] }\n"
       spago ["-x", "alternative2.dhall", "install", "simple-json"] >>= shouldBeSuccess
-      spago ["-x", "alternative2.dhall", "install", "simple-json"] >>= shouldBeSuccessOutput "alternative2install.txt"
+      spago ["-x", "alternative2.dhall", "install", "simple-json"] >>= shouldBeSuccessOutputWithErr "alternative2install.txt" "alternative2install-warning.txt"
       checkFixture "alternative2.dhall"
 
     it "Spago should install successfully when there are local dependencies sharing the same packages.dhall" $ do
@@ -521,16 +523,15 @@ spec = around_ setup $ do
       spago ["build"] >>= shouldBeSuccess
 
       shell "psa --version" empty >>= \case
-        ExitSuccess -> spago ["-v", "run"] >>= shouldBeSuccessOutput "run-output.txt"
-        ExitFailure _ ->  spago ["-v", "run"] >>= shouldBeSuccessOutput "run-output-psa-not-installed.txt"
+        ExitSuccess -> spago ["-v", "run"] >>= shouldBeSuccessOutputWithErr "run-output.txt" "run-output-err.txt"
+        ExitFailure _ ->  spago ["-v", "run"] >>= shouldBeSuccessOutputWithErr "run-output-psa-not-installed.txt" "run-output-psa-not-installed-err.txt"
 
     it "Spago should be able to not use `psa`" $ do
 
       spago ["init"] >>= shouldBeSuccess
       spago ["--no-psa", "build"] >>= shouldBeSuccess
       spago ["--no-psa", "build"] >>= shouldBeSuccess
-      spago ["-v", "--no-psa", "run"] >>= shouldBeSuccessOutput "run-no-psa.txt"
-
+      spago ["-v", "--no-psa", "run"] >>= shouldBeSuccessOutputWithErr "run-no-psa.txt" "run-no-psa-err.txt"
 
   describe "spago bundle" $ do
 
@@ -598,6 +599,7 @@ spec = around_ setup $ do
       rm "packages.dhall"
       writeTextFile "packages.dhall" $ "../packages.dhall"
       spago ["path", "output"] >>= outputShouldEqual "./../output\n"
+      pure ()
 
     it "Spago should output the local path when no overrides" $ do
 
diff --git a/test/Utils.hs b/test/Utils.hs
index db67c89f1..d6efbcc75 100644
--- a/test/Utils.hs
+++ b/test/Utils.hs
@@ -13,6 +13,7 @@ module Utils
   , shouldBeSuccess
   , shouldBeSuccessInfix
   , shouldBeSuccessOutput
+  , shouldBeSuccessOutputWithErr
   , shouldBeEmptySuccess
   , spago
   , withCwd
@@ -27,6 +28,7 @@ import qualified System.Process     as Process
 import           Test.Hspec         (HasCallStack, shouldBe, shouldSatisfy)
 import           Turtle             (ExitCode (..), FilePath, Text, cd, empty, encodeString, inproc,
                                      limit, procStrictWithErr, pwd, readTextFile, strict)
+import Data.Char (isControl)
 
 withCwd :: FilePath -> IO () -> IO ()
 withCwd dir cmd = do
@@ -63,6 +65,14 @@ shouldBeSuccessOutput expected (code, stdout, _stderr) = do
   code `shouldBe` ExitSuccess
   stdout `shouldBe` expectedStdout
 
+shouldBeSuccessOutputWithErr :: HasCallStack => FilePath -> FilePath -> (ExitCode, Text, Text) -> IO ()
+shouldBeSuccessOutputWithErr expected expectedErr (code, stdout, stderr) = do
+  expectedStdout <- readFixture expected
+  expectedStderr <- readFixture expectedErr
+  code `shouldBe` ExitSuccess
+  stdout `shouldBe` expectedStdout
+  stderr `shouldBe` expectedStderr
+
 shouldBeSuccessInfix :: HasCallStack => Text -> (ExitCode, Text, Text) -> IO ()
 shouldBeSuccessInfix expected (code, stdout, _stderr) = do
   code `shouldBe` ExitSuccess
diff --git a/test/fixtures/alternative2install-warning.txt b/test/fixtures/alternative2install-warning.txt
new file mode 100644
index 000000000..e014990fc
--- /dev/null
+++ b/test/fixtures/alternative2install-warning.txt
@@ -0,0 +1,2 @@
+WARNING: Failed to add dependencies. You should have a record with the `dependencies` key for this to work.
+WARNING: configuration file was not updated.
diff --git a/test/fixtures/alternative2install.txt b/test/fixtures/alternative2install.txt
index 2a4b5cc0e..c9d6c6305 100644
--- a/test/fixtures/alternative2install.txt
+++ b/test/fixtures/alternative2install.txt
@@ -1,3 +1 @@
-WARNING: Failed to add dependencies. You should have a record with the `dependencies` key for this to work.
-WARNING: configuration file was not updated.
 Installation complete.
diff --git a/test/fixtures/run-no-psa-err.txt b/test/fixtures/run-no-psa-err.txt
new file mode 100644
index 000000000..b1bc03521
--- /dev/null
+++ b/test/fixtures/run-no-psa-err.txt
@@ -0,0 +1,15 @@
+Transformed config is the same as the read one, not overwriting it
+Ensuring that the package set is frozen
+Running with backend: nodejs
+Running `spago build`
+Transformed config is the same as the read one, not overwriting it
+Ensuring that the package set is frozen
+Getting transitive deps
+Running `fetchPackages`
+Checking if `purs` is up to date
+Running `getGlobalCacheDir`
+Locating root path of packages.dhall
+Compiling with "purs"
+Running command: `purs compile --output ./output ".spago/console/v4.2.0/src/**/*.purs" ".spago/effect/v2.0.1/src/**/*.purs" ".spago/prelude/v4.1.1/src/**/*.purs" ".spago/psci-support/v4.0.0/src/**/*.purs" "src/**/*.purs" "test/**/*.purs"`
+Locating root path of packages.dhall
+Writing .spago/run.js
diff --git a/test/fixtures/run-no-psa.txt b/test/fixtures/run-no-psa.txt
index 05778e256..f8b3c4c9d 100644
--- a/test/fixtures/run-no-psa.txt
+++ b/test/fixtures/run-no-psa.txt
@@ -1,18 +1,3 @@
 🍝
-Transformed config is the same as the read one, not overwriting it
-Ensuring that the package set is frozen
-Running with backend: nodejs
-Running `spago build`
-Transformed config is the same as the read one, not overwriting it
-Ensuring that the package set is frozen
-Getting transitive deps
-Running `fetchPackages`
-Checking if `purs` is up to date
-Running `getGlobalCacheDir`
 Installation complete.
-Locating root path of packages.dhall
-Compiling with "purs"
-Running command: `purs compile --output ./output ".spago/console/v4.2.0/src/**/*.purs" ".spago/effect/v2.0.1/src/**/*.purs" ".spago/prelude/v4.1.1/src/**/*.purs" ".spago/psci-support/v4.0.0/src/**/*.purs" "src/**/*.purs" "test/**/*.purs"`
 Build succeeded.
-Locating root path of packages.dhall
-Writing .spago/run.js
diff --git a/test/fixtures/run-output-err.txt b/test/fixtures/run-output-err.txt
new file mode 100644
index 000000000..7c1d42727
--- /dev/null
+++ b/test/fixtures/run-output-err.txt
@@ -0,0 +1,18 @@
+Transformed config is the same as the read one, not overwriting it
+Ensuring that the package set is frozen
+Running with backend: nodejs
+Running `spago build`
+Transformed config is the same as the read one, not overwriting it
+Ensuring that the package set is frozen
+Getting transitive deps
+Running `fetchPackages`
+Checking if `purs` is up to date
+Running `getGlobalCacheDir`
+Locating root path of packages.dhall
+Compiling with "psa"
+Running command: `psa compile --output ./output ".spago/console/v4.2.0/src/**/*.purs" ".spago/effect/v2.0.1/src/**/*.purs" ".spago/prelude/v4.1.1/src/**/*.purs" ".spago/psci-support/v4.0.0/src/**/*.purs" "src/**/*.purs" "test/**/*.purs"`
+           Src   Lib   All
+Warnings   0     0     0  
+Errors     0     0     0  
+Locating root path of packages.dhall
+Writing .spago/run.js
diff --git a/test/fixtures/run-output-psa-not-installed-err.txt b/test/fixtures/run-output-psa-not-installed-err.txt
new file mode 100644
index 000000000..b1bc03521
--- /dev/null
+++ b/test/fixtures/run-output-psa-not-installed-err.txt
@@ -0,0 +1,15 @@
+Transformed config is the same as the read one, not overwriting it
+Ensuring that the package set is frozen
+Running with backend: nodejs
+Running `spago build`
+Transformed config is the same as the read one, not overwriting it
+Ensuring that the package set is frozen
+Getting transitive deps
+Running `fetchPackages`
+Checking if `purs` is up to date
+Running `getGlobalCacheDir`
+Locating root path of packages.dhall
+Compiling with "purs"
+Running command: `purs compile --output ./output ".spago/console/v4.2.0/src/**/*.purs" ".spago/effect/v2.0.1/src/**/*.purs" ".spago/prelude/v4.1.1/src/**/*.purs" ".spago/psci-support/v4.0.0/src/**/*.purs" "src/**/*.purs" "test/**/*.purs"`
+Locating root path of packages.dhall
+Writing .spago/run.js
diff --git a/test/fixtures/run-output-psa-not-installed.txt b/test/fixtures/run-output-psa-not-installed.txt
index 05778e256..f8b3c4c9d 100644
--- a/test/fixtures/run-output-psa-not-installed.txt
+++ b/test/fixtures/run-output-psa-not-installed.txt
@@ -1,18 +1,3 @@
 🍝
-Transformed config is the same as the read one, not overwriting it
-Ensuring that the package set is frozen
-Running with backend: nodejs
-Running `spago build`
-Transformed config is the same as the read one, not overwriting it
-Ensuring that the package set is frozen
-Getting transitive deps
-Running `fetchPackages`
-Checking if `purs` is up to date
-Running `getGlobalCacheDir`
 Installation complete.
-Locating root path of packages.dhall
-Compiling with "purs"
-Running command: `purs compile --output ./output ".spago/console/v4.2.0/src/**/*.purs" ".spago/effect/v2.0.1/src/**/*.purs" ".spago/prelude/v4.1.1/src/**/*.purs" ".spago/psci-support/v4.0.0/src/**/*.purs" "src/**/*.purs" "test/**/*.purs"`
 Build succeeded.
-Locating root path of packages.dhall
-Writing .spago/run.js
diff --git a/test/fixtures/run-output.txt b/test/fixtures/run-output.txt
index e2a8ddd99..f8b3c4c9d 100644
--- a/test/fixtures/run-output.txt
+++ b/test/fixtures/run-output.txt
@@ -1,18 +1,3 @@
 🍝
-Transformed config is the same as the read one, not overwriting it
-Ensuring that the package set is frozen
-Running with backend: nodejs
-Running `spago build`
-Transformed config is the same as the read one, not overwriting it
-Ensuring that the package set is frozen
-Getting transitive deps
-Running `fetchPackages`
-Checking if `purs` is up to date
-Running `getGlobalCacheDir`
 Installation complete.
-Locating root path of packages.dhall
-Compiling with "psa"
-Running command: `psa compile --output ./output ".spago/console/v4.2.0/src/**/*.purs" ".spago/effect/v2.0.1/src/**/*.purs" ".spago/prelude/v4.1.1/src/**/*.purs" ".spago/psci-support/v4.0.0/src/**/*.purs" "src/**/*.purs" "test/**/*.purs"`
 Build succeeded.
-Locating root path of packages.dhall
-Writing .spago/run.js
diff --git a/test/fixtures/spago-install-existing-dep-output.txt b/test/fixtures/spago-install-existing-dep-output.txt
new file mode 100644
index 000000000..c9d6c6305
--- /dev/null
+++ b/test/fixtures/spago-install-existing-dep-output.txt
@@ -0,0 +1 @@
+Installation complete.
diff --git a/test/fixtures/spago-install-existing-dep-warning.txt b/test/fixtures/spago-install-existing-dep-warning.txt
index 5feb72645..9122e82e7 100644
--- a/test/fixtures/spago-install-existing-dep-warning.txt
+++ b/test/fixtures/spago-install-existing-dep-warning.txt
@@ -1,2 +1 @@
 WARNING: configuration file was not updated.
-Installation complete.