diff --git a/Makefile b/Makefile
index e4cbbd8..0effd09 100644
--- a/Makefile
+++ b/Makefile
@@ -5,11 +5,23 @@ STUNAME = 张三
 
 GITFLAGS = -q --author='tracer-ysyx2204 <tracer@ysyx.org>' --no-verify --allow-empty
 
+WORK_BRANCH = $(shell git rev-parse --abbrev-ref HEAD)
+TRACER_BRANCH = ysyx-tracer
+
 # prototype: git_commit(msg)
 define git_commit
-	-@git add .. -A --ignore-errors
-	-@while (test -e .git/index.lock); do sleep 0.1; done
-	-@(echo "> $(1)" && echo $(STUID) $(STUNAME) && uname -a && uptime) | git commit -F - $(GITFLAGS)
+	-@cd $(YSYX_HOME) && while (test -e .git/index.lock); do sleep 0.1; done;  `# wait for other git instances`
+	-@cd $(YSYX_HOME) && git branch $(TRACER_BRANCH) -q 2>/dev/null || true    `# create tracer branch if not existent`
+	-@cd $(YSYX_HOME) && git worktree add $(TRACER_BRANCH) -q                  `# check out tracer branch`
+	-@cd $(YSYX_HOME) && git status --untracked-files -z                       `# list changed files to copy (w/o quotes)` \
+			| tr '\000' '\n'                                           `# restore EOL sequence`                    \
+			| cut -c 1-3 --complement                                  `# remove status indicator`                 \
+			| grep -v '^$(TRACER_BRANCH)/'                             `# skip tracer worktree`                    \
+			| rsync -aq --files-from=- ./ $(TRACER_BRANCH)/            `# call rsync to copy files`
+	-@cd $(YSYX_HOME) && git -C $(TRACER_BRANCH) add . -A --ignore-errors      `# add changes to staging area`
+	-@cd $(YSYX_HOME) && (echo "> $(1)" && echo $(STUID) $(STUNAME) && uname -a && uptime `# generate commit msg`)         \
+			| git -C $(TRACER_BRANCH) commit -F - $(GITFLAGS)          `# commit changes in tracer branch`
+	-@cd $(YSYX_HOME) && git worktree remove $(TRACER_BRANCH) -f               `# remove tracer worktree`
 	-@sync
 endef
 
diff --git a/init.sh b/init.sh
index 5a7a3ff..3b44360 100644
--- a/init.sh
+++ b/init.sh
@@ -66,6 +66,14 @@ case $1 in
     sed -i -e "/^export NPC_HOME=.*/d" ~/.bashrc
     echo "export NPC_HOME=`readlink -e npc`" >> ~/.bashrc
 
+    echo "By default this script will add environment variables into ~/.bashrc."
+    echo "After that, please run 'source ~/.bashrc' to let these variables take effect."
+    echo "If you use shell other than bash, please add these environment variables manually."
+    ;;
+  ysyx)
+    sed -i -e "/^export YSYX_HOME=.*/d" ~/.bashrc
+    echo "export YSYX_HOME=`readlink -e .`" >> ~/.bashrc
+
     echo "By default this script will add environment variables into ~/.bashrc."
     echo "After that, please run 'source ~/.bashrc' to let these variables take effect."
     echo "If you use shell other than bash, please add these environment variables manually."