c189e8b40c2a9ed15850d5bb5a68e6789be5fc70

 1diff --git a/themes/agnoster.zsh-theme b/themes/agnoster.zsh-theme
 2index 5f4efe813b4aadc49efa42d30fbbe8d8c2c43cf7..88854eccd924dfb5032c8048c542c59f31e6b829 100644
 3--- a/themes/agnoster.zsh-theme
 4+++ b/themes/agnoster.zsh-theme
 5@@ -116,6 +116,17 @@ prompt_git() {
 6       prompt_segment green $CURRENT_FG
 7     fi
 8 
 9+    local ahead behind
10+    ahead=$(git log --oneline @{upstream}.. 2>/dev/null)
11+    behind=$(git log --oneline ..@{upstream} 2>/dev/null)
12+    if [[ -n "$ahead" ]] && [[ -n "$behind" ]]; then
13+      PL_BRANCH_CHAR=$'\u21c5'
14+    elif [[ -n "$ahead" ]]; then
15+      PL_BRANCH_CHAR=$'\u21b1'
16+    elif [[ -n "$behind" ]]; then
17+      PL_BRANCH_CHAR=$'\u21b0'
18+    fi
19+
20     if [[ -e "${repo_path}/BISECT_LOG" ]]; then
21       mode=" <B>"
22     elif [[ -e "${repo_path}/MERGE_HEAD" ]]; then