diff --git a/mit-3qvpPyAi6mH.cabal b/mit-3qvpPyAi6mH.cabal
--- a/mit-3qvpPyAi6mH.cabal
+++ b/mit-3qvpPyAi6mH.cabal
@@ -11,7 +11,7 @@
 name: mit-3qvpPyAi6mH
 stability: experimental
 synopsis: A git wrapper with a streamlined UX
-version: 4
+version: 5
 
 description:
   A git wrapper with a streamlined UX.
@@ -23,18 +23,18 @@
 
 common component
   build-depends:
-    base < 5,
-    base64,
-    containers,
-    clock,
-    directory,
-    ki,
-    process,
-    record-dot-preprocessor,
-    record-hasfield,
-    text,
-    text-ansi,
-    unix,
+    base == 4.14.3.0,
+    base64 == 0.4.2.3,
+    containers == 0.6.5.1,
+    clock == 0.8.2,
+    directory == 1.3.6.0,
+    ki == 0.2.0.1,
+    process == 1.6.13.2,
+    record-dot-preprocessor == 0.2.13,
+    record-hasfield == 1.0,
+    text == 1.2.5.0,
+    text-ansi == 0.1.1,
+    unix == 2.7.2.2,
   default-extensions:
     BlockArguments
     DataKinds
diff --git a/src/Mit.hs b/src/Mit.hs
--- a/src/Mit.hs
+++ b/src/Mit.hs
@@ -7,8 +7,12 @@
 import qualified Data.Sequence as Seq
 import qualified Data.Text as Text
 import qualified Data.Text.ANSI as Text
+import qualified Data.Text.Builder.ANSI as Text.Builder
 import qualified Data.Text.Encoding.Base64 as Text
 import qualified Data.Text.IO as Text
+import qualified Data.Text.Lazy as Text.Lazy
+import qualified Data.Text.Lazy.Builder as Text (Builder)
+import qualified Data.Text.Lazy.Builder as Text.Builder
 import Mit.Git
 import Mit.Prelude
 import qualified Mit.Seq1 as Seq1
@@ -103,7 +107,7 @@
     Nothing ->
       doesDirectoryExist (Text.unpack worktreeDir) >>= \case
         False -> do
-          git_ ["worktree", "add", "--detach", worktreeDir]
+          gitl_ ["worktree", "add", "--detach", worktreeDir]
           withCurrentDirectory (Text.unpack worktreeDir) do
             gitBranchExists branch >>= \case
               False -> do
@@ -112,8 +116,8 @@
                 gitFetch_ "origin"
                 whenM (gitRemoteBranchExists "origin" branch) do
                   let upstream = "origin/" <> branch
-                  git_ ["reset", "--hard", upstream]
-                  git_ ["branch", "--set-upstream-to", upstream]
+                  gitl_ ["reset", "--hard", upstream]
+                  gitl_ ["branch", "--set-upstream-to", upstream]
               True -> gitSwitch branch
         True -> die ["Directory " <> Text.bold worktreeDir <> " already exists."]
     Just directory ->
@@ -148,9 +152,8 @@
 
   let wouldFork = existRemoteCommits && not existLocalCommits
   let shouldWarnAboutFork =
-        case wouldFork of
-          False -> pure False
-          True -> do
+        if wouldFork
+          then do
             let theyRanMitCommitRecently =
                   case state0.ranCommitAt of
                     Nothing -> pure False
@@ -158,6 +161,7 @@
                       t1 <- Clock.toNanoSecs <$> Clock.getTime Clock.Realtime
                       pure ((t1 - t0) < 10_000_000_000)
             not <$> theyRanMitCommitRecently
+          else pure False
 
   -- Bail out early if we should warn that this commit would fork history
   whenM shouldWarnAboutFork do
@@ -238,10 +242,10 @@
   state0 <- readMitState branch64
 
   case state0.merging of
-    Nothing -> git_ ["commit", "--all", "--no-edit"]
+    Nothing -> gitl_ ["commit", "--all", "--no-edit"]
     Just merging ->
       let message = fold ["⅄ ", if merging == branch then "" else merging <> " → ", branch]
-       in git_ ["commit", "--all", "--message", message]
+       in gitl_ ["commit", "--all", "--message", message]
   case listToMaybe [commit | Apply commit <- state0.undos] of
     Nothing -> mitSyncWith (Just [Reset head])
     Just stash ->
@@ -355,7 +359,7 @@
       maybeStash <- gitStash
       let undos = Reset head : maybeToList (Apply <$> maybeStash)
       result <-
-        git ["merge", "--ff", "--no-commit", target] >>= \case
+        gitl ["merge", "--ff", "--no-commit", target] >>= \case
           False -> do
             conflicts <- gitConflicts
             -- error: The following untracked working tree files would be overwritten by merge:
@@ -379,7 +383,7 @@
             -- Aborting
             pure (MergeResult'MergeConflicts (List1.fromList conflicts))
           True -> do
-            whenM gitMergeInProgress (git_ ["commit", "--message", message])
+            whenM gitMergeInProgress (gitl_ ["commit", "--message", message])
             maybeConflicts <- for maybeStash gitApplyStash
             pure (MergeResult'StashConflicts (fromMaybe [] maybeConflicts))
       pure (Just MergeStatus {commits, result, undos})
@@ -539,36 +543,39 @@
 putSummary :: Summary -> IO ()
 putSummary summary =
   let output = concatMap syncLines summary.syncs ++ conflictsLines ++ undoLines
-   in if null output then pure () else putLines ("" : output)
+   in if null output then pure () else putLines (map (Text.Lazy.toStrict . Text.Builder.toLazyText) ("" : output))
   where
-    conflictsLines :: [Text]
+    conflictsLines :: [Text.Builder]
     conflictsLines =
       if null summary.conflicts
         then []
         else
           "  The following files have conflicts." :
-          map (("    " <>) . Text.red . showGitConflict) summary.conflicts ++ [""]
-    syncLines :: Sync -> [Text]
+          map (("    " <>) . Text.Builder.red . showGitConflict) summary.conflicts ++ [""]
+    syncLines :: Sync -> [Text.Builder]
     syncLines sync =
-      colorize (Text.italic ("  " <> sync.source <> " → " <> sync.target)) :
+      colorize
+        ( Text.Builder.italic
+            ("  " <> Text.Builder.fromText sync.source <> " → " <> Text.Builder.fromText sync.target)
+        ) :
       map (("  " <>) . prettyGitCommitInfo) (toList @Seq commits')
         ++ (if more then ["  ...", ""] else [""])
       where
-        colorize :: Text -> Text
+        colorize :: Text.Builder -> Text.Builder
         colorize =
           case sync.result of
-            SyncResult'Failure -> Text.red
-            SyncResult'Offline -> Text.brightBlack
-            SyncResult'Pending -> Text.yellow
-            SyncResult'Success -> Text.green
+            SyncResult'Failure -> Text.Builder.red
+            SyncResult'Offline -> Text.Builder.brightBlack
+            SyncResult'Pending -> Text.Builder.yellow
+            SyncResult'Success -> Text.Builder.green
         (commits', more) =
           case Seq1.length sync.commits > 10 of
             False -> (Seq1.toSeq sync.commits, False)
             True -> (Seq1.dropEnd 1 sync.commits, True)
-    undoLines :: [Text]
+    undoLines :: [Text.Builder]
     undoLines =
       if summary.canUndo
-        then ["  Run " <> Text.bold (Text.blue "mit undo") <> " to undo this change.", ""]
+        then ["  Run " <> Text.Builder.bold (Text.Builder.blue "mit undo") <> " to undo this change.", ""]
         else []
 
 -- State file
diff --git a/src/Mit/Git.hs b/src/Mit/Git.hs
--- a/src/Mit/Git.hs
+++ b/src/Mit/Git.hs
@@ -6,7 +6,11 @@
 import qualified Data.Sequence as Seq
 import qualified Data.Text as Text
 import qualified Data.Text.ANSI as Text
+import qualified Data.Text.Builder.ANSI as Text.Builder
 import qualified Data.Text.IO as Text
+import qualified Data.Text.Lazy as Text.Lazy
+import qualified Data.Text.Lazy.Builder as Text (Builder)
+import qualified Data.Text.Lazy.Builder as Text.Builder
 import qualified Ki
 import Mit.Globals (debug)
 import Mit.Prelude
@@ -46,17 +50,16 @@
   }
   deriving stock (Show)
 
-prettyGitCommitInfo :: GitCommitInfo -> Text
+prettyGitCommitInfo :: GitCommitInfo -> Text.Builder
 prettyGitCommitInfo info =
-  -- FIXME use builder
   fold
-    [ Text.bold (Text.black info.shorthash),
+    [ Text.Builder.bold (Text.Builder.black (Text.Builder.fromText info.shorthash)),
       " ",
-      Text.bold (Text.white info.subject),
+      Text.Builder.bold (Text.Builder.white (Text.Builder.fromText info.subject)),
       " - ",
-      Text.italic (Text.white info.author),
+      Text.Builder.italic (Text.Builder.white (Text.Builder.fromText info.author)),
       " ",
-      Text.italic (Text.yellow info.date) -- FIXME some other color, magenta?
+      Text.Builder.italic (Text.Builder.yellow (Text.Builder.fromText info.date)) -- FIXME some other color, magenta?
     ]
 
 data GitConflict
@@ -68,10 +71,9 @@
   [xy, name] <- Just (Text.words line)
   GitConflict <$> parseGitConflictXY xy <*> Just name
 
--- FIXME builder
-showGitConflict :: GitConflict -> Text
+showGitConflict :: GitConflict -> Text.Builder
 showGitConflict (GitConflict xy name) =
-  name <> " (" <> showGitConflictXY xy <> ")"
+  Text.Builder.fromText name <> " (" <> showGitConflictXY xy <> ")"
 
 data GitConflictXY
   = AA -- both added
@@ -94,8 +96,7 @@
   "UU" -> Just UU
   _ -> Nothing
 
--- FIXME builder
-showGitConflictXY :: GitConflictXY -> Text
+showGitConflictXY :: GitConflictXY -> Text.Builder
 showGitConflictXY = \case
   AA -> "both added"
   AU -> "added by us"
@@ -117,7 +118,7 @@
 gitApplyStash :: Text -> IO [GitConflict]
 gitApplyStash stash = do
   conflicts <-
-    git ["stash", "apply", stash] >>= \case
+    gitl ["stash", "apply", stash] >>= \case
       False -> gitConflicts
       True -> pure []
   gitUnstageChanges
@@ -126,7 +127,7 @@
 -- | Create a branch.
 gitBranch :: Text -> IO ()
 gitBranch branch =
-  git_ ["branch", "--no-track", branch]
+  gitl_ ["branch", "--no-track", branch]
 
 -- | Does the given local branch (refs/heads/...) exist?
 gitBranchExists :: Text -> IO Bool
@@ -144,18 +145,18 @@
 gitBranchWorktreeDir :: Text -> IO (Maybe Text)
 gitBranchWorktreeDir branch = do
   worktrees <- gitWorktreeList
-  case List.find (\worktree -> worktree.branch == Just branch) worktrees of
-    Nothing -> pure Nothing
-    Just worktree -> pure (Just worktree.directory)
+  pure case List.find (\worktree -> worktree.branch == Just branch) worktrees of
+    Nothing -> Nothing
+    Just worktree -> Just worktree.directory
 
 gitCommit :: IO Bool
 gitCommit =
   queryTerminal 0 >>= \case
     False -> do
       message <- lookupEnv "MIT_COMMIT_MESSAGE"
-      git ["commit", "--all", "--message", maybe "" Text.pack message]
+      gitl ["commit", "--all", "--message", maybe "" Text.pack message]
     True ->
-      git2 ["commit", "--patch", "--quiet"] <&> \case
+      gitl2 ["commit", "--patch", "--quiet"] <&> \case
         ExitFailure _ -> False
         ExitSuccess -> True
 
@@ -194,7 +195,7 @@
 gitCreateStash :: IO Text
 gitCreateStash = do
   git_ ["add", "--all"] -- it seems certain things (like renames), unless staged, cannot be stashed
-  stash <- git ["stash", "create"]
+  stash <- gitl ["stash", "create"]
   gitUnstageChanges
   pure stash
 
@@ -224,7 +225,7 @@
 
 gitFetch :: Text -> IO Bool
 gitFetch remote =
-  git ["fetch", remote]
+  gitl ["fetch", remote]
 
 gitFetch_ :: Text -> IO ()
 gitFetch_ =
@@ -242,30 +243,31 @@
 -- FIXME document what this does
 gitMerge :: Text -> Text -> IO (Either (IO [GitConflict]) ())
 gitMerge me target = do
-  git ["merge", "--ff", "--no-commit", target] >>= \case
+  gitl ["merge", "--ff", "--no-commit", target] >>= \case
     False ->
       (pure . Left) do
         conflicts <- gitConflicts
-        git_ ["add", "--all"]
-        git_ ["commit", "--no-edit", "--message", mergeMessage conflicts]
+        gitl_ ["add", "--all"]
+        gitl_ ["commit", "--no-edit", "--message", mergeMessage conflicts]
         pure conflicts
     True -> do
-      whenM gitMergeInProgress (git_ ["commit", "--message", mergeMessage []])
+      whenM gitMergeInProgress (gitl_ ["commit", "--message", mergeMessage []])
       pure (Right ())
   where
     mergeMessage :: [GitConflict] -> Text
     mergeMessage conflicts =
-      -- FIXME use builder
-      fold
+      (Text.Lazy.toStrict . Text.Builder.toLazyText . fold)
         [ "⅄",
           if null conflicts then "" else "\x0338",
           " ",
-          if target' == me then me else target' <> " → " <> me,
+          if target' == me
+            then Text.Builder.fromText me
+            else Text.Builder.fromText target' <> " → " <> Text.Builder.fromText me,
           if null conflicts
             then ""
             else
               " (conflicts)\n\nConflicting files:\n"
-                <> Text.intercalate "\n" (map (("  " <>) . showGitConflict) conflicts)
+                <> mconcat (List.intersperse "\n" (map (("  " <>) . showGitConflict) conflicts))
         ]
       where
         target' :: Text
@@ -278,7 +280,7 @@
 
 gitPush :: Text -> IO Bool
 gitPush branch =
-  git ["push", "--set-upstream", "origin", branch <> ":" <> branch]
+  gitl ["push", "--set-upstream", "origin", branch <> ":" <> branch]
 
 -- | Does the given remote branch (refs/remotes/...) exist?
 gitRemoteBranchExists :: Text -> Text -> IO Bool
@@ -295,12 +297,12 @@
 -- | Blow away untracked files, and hard-reset to the given commit
 gitResetHard :: Text -> IO ()
 gitResetHard commit = do
-  git_ ["clean", "-d", "--force"]
-  git ["reset", "--hard", commit]
+  gitl_ ["clean", "-d", "--force"]
+  gitl ["reset", "--hard", commit]
 
 gitRevert :: Text -> IO ()
 gitRevert commit =
-  git_ ["revert", commit]
+  gitl_ ["revert", commit]
 
 -- | Stash uncommitted changes (if any).
 gitStash :: IO (Maybe Text)
@@ -318,9 +320,9 @@
 
 gitUnstageChanges :: IO ()
 gitUnstageChanges = do
-  git_ ["reset", "--mixed"]
+  gitl_ ["reset", "--mixed"]
   untrackedFiles <- gitListUntrackedFiles
-  unless (null untrackedFiles) (git_ ("add" : "--intent-to-add" : untrackedFiles))
+  unless (null untrackedFiles) (gitl_ ("add" : "--intent-to-add" : untrackedFiles))
 
 gitVersion :: IO GitVersion
 gitVersion = do
@@ -363,7 +365,15 @@
   pure (url, Text.takeWhileEnd (/= '/') url')
 
 git :: ProcessOutput a => [Text] -> IO a
-git args = do
+git =
+  git' False
+
+gitl :: ProcessOutput a => [Text] -> IO a
+gitl =
+  git' True
+
+git' :: ProcessOutput a => Bool -> [Text] -> IO a
+git' effectful args = do
   let spec :: CreateProcess
       spec =
         CreateProcess
@@ -384,6 +394,7 @@
             detach_console = False,
             use_process_jobs = False
           }
+  when effectful (logProcess "git" args)
   bracket (createProcess spec) cleanup \(_maybeStdin, maybeStdout, maybeStderr, processHandle) ->
     Ki.scoped \scope -> do
       stdoutThread <- Ki.fork scope (drainTextHandle (fromJust maybeStdout))
@@ -417,9 +428,14 @@
 git_ =
   git
 
+gitl_ :: [Text] -> IO ()
+gitl_ =
+  gitl
+
 -- Yucky interactive/inherity variant (so 'git commit' can open an editor).
-git2 :: [Text] -> IO ExitCode
-git2 args = do
+gitl2 :: [Text] -> IO ExitCode
+gitl2 args = do
+  logProcess "git" args
   (Nothing, Nothing, Just stderrHandle, processHandle) <-
     createProcess
       CreateProcess
diff --git a/src/Mit/Process.hs b/src/Mit/Process.hs
--- a/src/Mit/Process.hs
+++ b/src/Mit/Process.hs
@@ -4,7 +4,22 @@
 
 import qualified Data.Sequence as Seq
 import Mit.Prelude
+import qualified Data.Text as Text
+import qualified Data.Text.IO as Text
+import qualified Data.Text.Lazy as Text.Lazy
+import qualified Data.List as List
+import qualified Data.Text.Builder.ANSI as Text.Builder
+import qualified Data.Text.Lazy.Builder as Text.Builder
 import System.Exit (ExitCode (..), exitWith)
+
+logProcess :: Text -> [Text] -> IO ()
+logProcess s0 ss =
+  Text.putStrLn (Text.Lazy.toStrict (Text.Builder.toLazyText line))
+  where
+    line = "» " <> Text.Builder.bold (Text.Builder.fromText s0 <> space <> formatArgs ss)
+    formatArgs = mconcat . List.intersperse space . map formatArg
+    formatArg s = Text.Builder.fromText (if Text.elem ' ' s then s else s)
+    space = Text.Builder.singleton ' '
 
 class ProcessOutput a where
   fromProcessOutput :: Seq Text -> Seq Text -> ExitCode -> IO a