如何在git中比较本地和远程分支树？

比较两个随机分支A和B，以查找有多少次A新提交B：

git rev-list --count B..A

A并B可能具有以下一种关系：

1. A并且B是无关的分支；
2. A与B；
3. A领先B;
4. A在后面B;
5. A与分歧B。

找出与的关系foo.sh：

#!/bin/bash

A=$1
B=$2

merge_base=$(git merge-base $A $B)
if [[ "${merge_base}" = "" ]];then
    echo "$A and $B are unrelated"
else
    num_new_to_A=$(git rev-list --count $A..$B)
    num_new_to_B=$(git rev-list --count $B..$A)
    if [[ "${num_new_to_A}" -eq 0 ]] && [[ "${num_new_to_B}" -eq 0 ]];then
        echo "$A is up-to-date with $B"
    elif [[ "${num_new_to_A}" -eq 0 ]] && [[ "${num_new_to_B}" -gt 0 ]];then
        echo "$A is ${num_new_to_B} commits ahead of $B"
    elif [[ "${num_new_to_A}" -gt 0 ]] && [[ "${num_new_to_B}" -eq 0 ]];then
        echo "$A is ${num_new_to_A} commits behind $B"
    elif [[ "${num_new_to_A}" -gt 0 ]] && [[ "${num_new_to_B}" -gt 0 ]];then
        echo "$A is diverged with $B, ${num_new_to_B} commits ahead and ${num_new_to_A} commits behind"
    else
        :
    fi
fi

比较master和origin/master：

bash foo.sh master origin/master