diff --git a/document/linux/config/bash/module/git.sh b/document/linux/config/bash/module/git.sh
index cc294df..42d10ce 100644
--- a/document/linux/config/bash/module/git.sh
+++ b/document/linux/config/bash/module/git.sh
@@ -7,7 +7,6 @@ alias gst="git stash"
 alias gd="git diff"
 alias gc="git commit -m"
 alias gch="git checkout"
-alias gr="git rebase -i"
 alias gb="git branch"
 alias gco="git checkout"
 alias gf="git fetch"
@@ -28,3 +27,21 @@ ga()
   git diff $@
   git add $@
 }
+
+# rebase by X commits or from root.
+gr()
+{
+  local base="${1}"
+
+  # rebase last 2 commits by default.
+  if [[ "${base}" = "" ]]; then
+    base="2"
+  fi
+
+  # if 0, rebase from root. else from specified base.
+  if [[ "${base}" = "0" ]]; then
+    git rebase -i --root
+  else
+    git rebase -i HEAD~${base}
+  fi
+}