impr: externalizez sh scripts

src/sh/cligit.sh

@@ -0,0 +1,25 @@
+if [ "${1:-}" = "--git-init" ]; then
+  shift
+  if [ -n "${GIT:-}" ]; then
+    err "Git already enabled"
+    return 1
+  fi
+  if ! command -v "git" >/dev/null; then
+    err "Git not installed"
+    return 1
+  fi
+  git -C "$ROOT" init
+  git -C "$ROOT" add -A
+  git -C "$ROOT" commit -m 'Initial commit: Start git tracking'
+  exit
+fi
+
+if [ "${1:-}" = "--git" ]; then
+  shift
+  if [ -z "${GIT:-}" ]; then
+    err "Git not supported, run \`$0 --git-init\` first"
+    return 1
+  fi
+  $GIT "$@"
+  exit
+fi