下面是一个Bash一行代码，比较了当前分支的HEAD提交哈希和它的远程上游分支，不需要大量的git获取或git拉取——需要干运行操作:

[ $(git rev-parse HEAD) = $(git ls-remote $(git rev-parse --abbrev-ref @{u} | \
sed 's/\// /g') | cut -f1) ] && echo up to date || echo not up to date

以下是这条有点密集的线是如何被分解的:

Commands are grouped and nested using $(x) Bash command-substitution syntax. git rev-parse --abbrev-ref @{u} returns an abbreviated upstream ref (e.g. origin/master), which is then converted into space-separated fields by the piped sed command, e.g. origin master. This string is fed into git ls-remote which returns the head commit of the remote branch. This command will communicate with the remote repository. The piped cut command extracts just the first field (the commit hash), removing the tab-separated reference string. git rev-parse HEAD returns the local commit hash. The Bash syntax [ a = b ] && x || y completes the one-liner: this is a Bash string-comparison = within a test construct [ test ], followed by and-list and or-list constructs && true || false.

下面的脚本运行良好。

changed=0
git remote update && git status -uno | grep -q 'Your branch is behind' && changed=1
if [ $changed = 1 ]; then
    git pull
    echo "Updated successfully";
else
    echo "Up-to-date"
fi

使用简单的regexp:

str=$(git status) 
if [[ $str =~ .*Your\ branch\ is\ behind.*by.*commits,\ and\ can\ be\ fast-forwarded ]]; then
    echo `date "+%Y-%m-%d %H:%M:%S"` "Needs pull"
else
    echo "Code is up to date"
fi

因为尼尔的回答对我帮助很大，这里是一个没有依赖关系的Python翻译:

import os
import logging
import subprocess

def check_for_updates(directory:str) -> None:
    """Check git repo state in respect to remote"""
    git_cmd = lambda cmd: subprocess.run(
        ["git"] + cmd,
        cwd=directory,
        stdout=subprocess.PIPE,
        check=True,
        universal_newlines=True).stdout.rstrip("\n")

    origin = git_cmd(["config", "--get", "remote.origin.url"])
    logging.debug("Git repo origin: %r", origin)
    for line in git_cmd(["fetch"]):
        logging.debug(line)
    local_sha = git_cmd(["rev-parse", "@"])
    remote_sha = git_cmd(["rev-parse", "@{u}"])
    base_sha = git_cmd(["merge-base", "@", "@{u}"])
    if local_sha == remote_sha:
        logging.info("Repo is up to date")
    elif local_sha == base_sha:
        logging.info("You need to pull")
    elif remote_sha == base_sha:
        logging.info("You need to push")
    else:
        logging.info("Diverged")

check_for_updates(os.path.dirname(__file__))

hth

我只是想把这篇文章作为一个实际的帖子，因为它很容易在评论中错过。

这个问题的正确答案来自@Jake Berger，非常感谢你，每个人都需要这个，每个人都在评论中错过了这个。 因此，对于每个纠结于此的人来说，这里是正确的答案，只需使用该命令的输出来了解是否需要进行git拉取。如果输出为0，那么显然没有什么要更新的。

@stackoverflow，给这家伙一个铃铛。 谢谢@杰克·伯格

# will give you the total number of "different" commits between the two
# Jake Berger Feb 5 '13 at 19:23
git rev-list HEAD...origin/master --count

我使用了一个基于Stephen Haberman回答的脚本版本:

if [ -n "$1" ]; then
    gitbin="git -C $1"
else
    gitbin="git"
fi

# Fetches from all the remotes, although --all can be replaced with origin
$gitbin fetch --all
if [ $($gitbin rev-parse HEAD) != $($gitbin rev-parse @{u}) ]; then
    $gitbin rebase @{u} --preserve-merges
fi

假设此脚本名为Git -fetch-and-rebase，可以使用本地Git存储库的可选参数目录名来调用它，以执行操作。如果调用脚本时不带参数，则假定当前目录是Git存储库的一部分。

例子:

# Operates on /abc/def/my-git-repo-dir
git-fetch-and-rebase /abc/def/my-git-repo-dir

# Operates on the Git repository which the current working directory is part of
git-fetch-and-rebase

这里也有。