Remote repository — clone, fetch, pull, push আর tracking branch

$ git init --bare server/bazar.git
Initialized empty Git repository in C:/…/t14/server/bazar.git/
$ cd rahim
$ git log --oneline
c4f7d9c Add README
be5e7dd Add shop config
$ git remote add origin ../server/bazar.git
$ git remote -v
origin	../server/bazar.git (fetch)
origin	../server/bazar.git (push)
$ git push -u origin main
To ../server/bazar.git
 * [new branch]      main -> main
branch 'main' set up to track 'origin/main'.
$ git branch -vv
* main c4f7d9c [origin/main] Add README
$ git config --get-regexp "^(remote|branch)\."
remote.origin.url ../server/bazar.git
remote.origin.fetch +refs/heads/*:refs/remotes/origin/*
branch.main.remote origin
branch.main.merge refs/heads/main
$ git ls-remote origin
c4f7d9cd9552be8b41fd33b713fd24641db0340d	HEAD
c4f7d9cd9552be8b41fd33b713fd24641db0340d	refs/heads/main

$ git clone server/bazar.git nasrin
Cloning into 'nasrin'...
done.
$ cd nasrin
$ git remote -v
origin	C:/…/t14/server/bazar.git (fetch)
origin	C:/…/t14/server/bazar.git (push)
$ git remote set-url origin ../server/bazar.git
$ git remote -v
origin	../server/bazar.git (fetch)
origin	../server/bazar.git (push)
$ git branch -a
* main
  remotes/origin/HEAD -> origin/main
  remotes/origin/main
$ git branch -vv
* main c4f7d9c [origin/main] Add README
$ git log --oneline --decorate --all
c4f7d9c (HEAD -> main, origin/main, origin/HEAD) Add README
be5e7dd Add shop config
$ git config --get-regexp "^(remote|branch)\."
remote.origin.url ../server/bazar.git
remote.origin.fetch +refs/heads/*:refs/remotes/origin/*
branch.main.remote origin
branch.main.merge refs/heads/main

// Ahead/behind by reachability: the commit graph of the Bazar Mart story (real hashes).
const parents = {
  be5e7dd: [], c4f7d9c: ["be5e7dd"], ec6020e: ["c4f7d9c"],
  e743a3a: ["c4f7d9c"],                       // Rahim's commit before the pull
  "23d6d2c": ["e743a3a", "ec6020e"],          // the merge made by git pull --no-rebase
  "41edf81": ["ec6020e"],                     // the same work after git pull --rebase
  e90c3b7: ["41edf81"], "4218834": ["e90c3b7"], "11fa2d8": ["41edf81"],
  a1f5d64: ["4218834"], "93710ae": ["41edf81", "a1f5d64"]
};
function reach(c) {                           // c and everything reachable through parents
  const seen = new Set([c]), stack = [c];
  while (stack.length)
    for (const p of parents[stack.pop()])
      if (!seen.has(p)) { seen.add(p); stack.push(p); }
  return seen;
}
function aheadBehind(local, remote) {         // like git rev-list --left-right --count local...remote
  const L = reach(local), R = reach(remote);
  const ahead = [...L].filter(c => !R.has(c)), behind = [...R].filter(c => !L.has(c));
  return { ahead, behind };
}
const cases = [
  ["e743a3a", "ec6020e", "Rahim after fetch"],
  ["23d6d2c", "ec6020e", "Rahim after pull --no-rebase"],
  ["41edf81", "93710ae", "Nasrin after fetch --prune"],
  ["11fa2d8", "e90c3b7", "Rahim after amend, stale"],
  ["11fa2d8", "4218834", "Rahim after amend + fetch"]
];
for (const [l, r, label] of cases) {
  const { ahead, behind } = aheadBehind(l, r);
  console.log(label.padEnd(29) + ahead.length + "\t" + behind.length +
    "   ahead: " + (ahead.join(" ") || "-") + " | behind: " + (behind.join(" ") || "-"));
}

# --- Nasrin ---
# (edit shop.conf: delivery_fee = 60 -> 50; git add shop.conf)
$ git commit -m "Lower delivery fee to 50"
[main ec6020e] Lower delivery fee to 50
 1 file changed, 1 insertion(+), 1 deletion(-)
$ git status -sb
## main...origin/main [ahead 1]
$ git push
To ../server/bazar.git
   c4f7d9c..ec6020e  main -> main
# --- Rahim (has not fetched) ---
# (add two lines to README.md; git add README.md)
$ git commit -m "Describe the shop in README"
[main e743a3a] Describe the shop in README
 1 file changed, 2 insertions(+)
$ git status
On branch main
Your branch is ahead of 'origin/main' by 1 commit.
  (use "git push" to publish your local commits)

nothing to commit, working tree clean
$ git push
To ../server/bazar.git
 ! [rejected]        main -> main (fetch first)
error: failed to push some refs to '../server/bazar.git'
hint: Updates were rejected because the remote contains work that you do not
hint: have locally. This is usually caused by another repository pushing to
hint: the same ref. If you want to integrate the remote changes, use
hint: 'git pull' before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.
$ git fetch
From ../server/bazar
   c4f7d9c..ec6020e  main       -> origin/main
$ git status
On branch main
Your branch and 'origin/main' have diverged,
and have 1 and 1 different commits each, respectively.
  (use "git pull" if you want to integrate the remote branch with yours)

nothing to commit, working tree clean
$ git rev-list --left-right --count main...origin/main
1	1
$ git log --oneline --graph --all
* e743a3a Describe the shop in README
| * ec6020e Lower delivery fee to 50
|/
* c4f7d9c Add README
* be5e7dd Add shop config

// Two clones and one shared remote. All commits live in one shared store here;
// real Git copies the objects during fetch and push.
const parents = { A: [] }, server = { main: "A" };       // commit -> its parents
const mk = () => ({ main: "A", "origin/main": "A" }), repos = { rahim: mk(), nasrin: mk() };
const anc = c => { const s = new Set(), q = [c];   // c and all its ancestors
  while (q.length) { const x = q.pop(); if (!s.has(x)) { s.add(x); q.push(...parents[x]); } }
  return s; };
const count = (a, b) => [...anc(a)].filter(c => !anc(b).has(c)).length;
function commit(r, id) { parents[id] = [repos[r].main]; repos[r].main = id; }
function fetchOrigin(r) { repos[r]["origin/main"] = server.main; }
function push(r) {
  const me = repos[r];
  if (!anc(me.main).has(server.main)) return "! [rejected] main -> main (fetch first)";
  server.main = me.main; me["origin/main"] = me.main; return "ok, server main = " + me.main;
}
function pull(r, id) {                            // fetch + merge
  fetchOrigin(r); const me = repos[r], t = me["origin/main"];
  if (anc(me.main).has(t)) return "Already up to date";
  if (anc(t).has(me.main)) { me.main = t; return "Fast-forward to " + t; }
  parents[id] = [me.main, t]; me.main = id; return "Merge commit " + id;
}
function show(step, msg) {                         // main/origin-main [ahead behind]
  let line = step.padEnd(20);
  for (const [n, r] of Object.entries(repos)) {
    const o = r["origin/main"];
    line += n + " " + r.main + "/" + o + " [" + count(r.main, o) + " " + count(o, r.main) + "]  ";
  }
  console.log(line + "server " + server.main + (msg ? "   " + msg : ""));
}
commit("nasrin", "B"); show("1 nasrin commits B");   show("2 nasrin pushes", push("nasrin"));
commit("rahim", "C");  show("3 rahim commits C");    show("4 rahim pushes", push("rahim"));
fetchOrigin("rahim");  show("5 rahim fetches");      show("6 rahim pulls", pull("rahim", "M"));
show("7 rahim pushes", push("rahim"));
fetchOrigin("nasrin"); show("8 nasrin fetches");     show("9 nasrin pulls", pull("nasrin", "X"));

$ git pull
hint: You have divergent branches and need to specify how to reconcile them.
hint: You can do so by running one of the following commands sometime before
hint: your next pull:
hint:
hint:   git config pull.rebase false  # merge
hint:   git config pull.rebase true   # rebase
hint:   git config pull.ff only       # fast-forward only
hint:
hint: You can replace "git config" with "git config --global" to set a default
hint: preference for all repositories. You can also pass --rebase, --no-rebase,
hint: or --ff-only on the command line to override the configured default per
hint: invocation.
fatal: Need to specify how to reconcile divergent branches.
$ git pull --no-rebase
Merge made by the 'ort' strategy.
 shop.conf | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
$ git log --oneline --graph -5
*   23d6d2c Merge branch 'main' of ../server/bazar
|\
| * ec6020e Lower delivery fee to 50
* | e743a3a Describe the shop in README
|/
* c4f7d9c Add README
* be5e7dd Add shop config
$ git status -sb
## main...origin/main [ahead 2]

$ git pull --rebase
Successfully rebased and updated refs/heads/main.
$ git log --oneline --graph --all
* 41edf81 Describe the shop in README
* ec6020e Lower delivery fee to 50
* c4f7d9c Add README
* be5e7dd Add shop config
$ git status -sb
## main...origin/main [ahead 1]
$ git push
To ../server/bazar.git
   ec6020e..41edf81  main -> main
# --- Nasrin ---
$ git fetch
From ../server/bazar
   ec6020e..41edf81  main       -> origin/main
$ git status
On branch main
Your branch is behind 'origin/main' by 1 commit, and can be fast-forwarded.
  (use "git pull" to update your local branch)

nothing to commit, working tree clean
$ git pull --ff-only
Updating ec6020e..41edf81
Fast-forward
 README.md | 2 ++
 1 file changed, 2 insertions(+)

# --- Rahim ---
$ git switch -c feature/wallet
Switched to a new branch 'feature/wallet'
# (create payment.conf; git add payment.conf)
$ git commit -m "Add mobile wallet payment"
[feature/wallet e90c3b7] Add mobile wallet payment
 1 file changed, 1 insertion(+)
 create mode 100644 payment.conf
$ git push
fatal: The current branch feature/wallet has no upstream branch.
To push the current branch and set the remote as upstream, use

    git push --set-upstream origin feature/wallet

To have this happen automatically for branches without a tracking
upstream, see 'push.autoSetupRemote' in 'git help config'.

$ git push -u origin feature/wallet
To ../server/bazar.git
 * [new branch]      feature/wallet -> feature/wallet
branch 'feature/wallet' set up to track 'origin/feature/wallet'.
$ git branch -vv
* feature/wallet e90c3b7 [origin/feature/wallet] Add mobile wallet payment
  main           41edf81 [origin/main] Describe the shop in README
# --- Nasrin ---
$ git switch -c feature/coupon
Switched to a new branch 'feature/coupon'
# (create coupon.conf, git add, git commit -m "Add eid coupon")
$ git config push.autoSetupRemote true
$ git push
To ../server/bazar.git
 * [new branch]      feature/coupon -> feature/coupon
branch 'feature/coupon' set up to track 'origin/feature/coupon'.

# --- Rahim ---
$ git switch main
Switched to branch 'main'
Your branch is up to date with 'origin/main'.
$ git merge --no-ff -m "Merge branch 'feature/wallet'" feature/wallet
Merge made by the 'ort' strategy.
 payment.conf | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 payment.conf
$ git push
To ../server/bazar.git
   41edf81..93710ae  main -> main
$ git push origin --delete feature/wallet
To ../server/bazar.git
 - [deleted]         feature/wallet
$ git branch -d feature/wallet
Deleted branch feature/wallet (was a1f5d64).
# --- Nasrin ---
$ git branch -vv
  feature/coupon 4408a83 [origin/feature/coupon] Add eid coupon
  feature/wallet 4218834 [origin/feature/wallet] Set minimum wallet payment
* main           41edf81 [origin/main] Describe the shop in README
$ git fetch --prune
From ../server/bazar
 - [deleted]         (none)     -> origin/feature/wallet
   41edf81..93710ae  main       -> origin/main
$ git branch -vv
  feature/coupon 4408a83 [origin/feature/coupon] Add eid coupon
  feature/wallet 4218834 [origin/feature/wallet: gone] Set minimum wallet payment
* main           41edf81 [origin/main: behind 4] Describe the shop in README
$ git pull --ff-only
Updating 41edf81..93710ae
Fast-forward
 payment.conf | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 payment.conf
$ git branch -d feature/wallet
Deleted branch feature/wallet (was 4218834).
$ git ls-remote origin
93710aeceb3c78fe37e8a63228c92d1b9d216365	HEAD
4408a83d090513788c31aca06f1421849a67a77c	refs/heads/feature/coupon
93710aeceb3c78fe37e8a63228c92d1b9d216365	refs/heads/main

# --- Nasrin ---
$ git fetch
From ../server/bazar
 * [new branch]      feature/wallet -> origin/feature/wallet
$ git switch feature/wallet
Switched to a new branch 'feature/wallet'
branch 'feature/wallet' set up to track 'origin/feature/wallet'.
# (add "min_amount = 20" to payment.conf; git add)
$ git commit -m "Set minimum wallet payment"
[feature/wallet 4218834] Set minimum wallet payment
 1 file changed, 1 insertion(+)
$ git push
To ../server/bazar.git
   e90c3b7..4218834  feature/wallet -> feature/wallet
# --- Rahim (has NOT fetched) ---
# (edit payment.conf: wallet -> mobile-wallet; git add)
$ git commit --amend -m "Add mobile-wallet payment method"
[feature/wallet 11fa2d8] Add mobile-wallet payment method
 Date: Tue Jan 20 10:06:00 2026 +0600
 1 file changed, 1 insertion(+)
 create mode 100644 payment.conf
$ git status -sb
## feature/wallet...origin/feature/wallet [ahead 1, behind 1]
$ git push
To ../server/bazar.git
 ! [rejected]        feature/wallet -> feature/wallet (fetch first)
error: failed to push some refs to '../server/bazar.git'
hint: Updates were rejected because the remote contains work that you do not
…
$ git push --force-with-lease
To ../server/bazar.git
 ! [rejected]        feature/wallet -> feature/wallet (stale info)
error: failed to push some refs to '../server/bazar.git'

$ git ls-remote origin refs/heads/feature/wallet
4218834c42fb0b29b8ed0c4ffe7a0d244cde5a30	refs/heads/feature/wallet
$ git push --force
To ../server/bazar.git
 + 4218834...11fa2d8 feature/wallet -> feature/wallet (forced update)
$ git ls-remote origin refs/heads/feature/wallet
11fa2d80680f31be471e339fa1aaa20a6a136821	refs/heads/feature/wallet

$ git fetch
From ../server/bazar
   e90c3b7..4218834  feature/wallet -> origin/feature/wallet
 * [new branch]      feature/coupon -> origin/feature/coupon
$ git status -sb
## feature/wallet...origin/feature/wallet [ahead 1, behind 2]
$ git push --force-with-lease
To ../server/bazar.git
 + 4218834...11fa2d8 feature/wallet -> feature/wallet (forced update)
# (server restored to 4218834 for the next try; Rahim fetches again)
$ git push --force-with-lease --force-if-includes
To ../server/bazar.git
 ! [rejected]        feature/wallet -> feature/wallet (remote ref updated since checkout)
error: failed to push some refs to '../server/bazar.git'
hint: Updates were rejected because the tip of the remote-tracking branch has
hint: been updated since the last checkout. If you want to integrate the
hint: remote changes, use 'git pull' before pushing again.
…

$ git rebase origin/feature/wallet
Auto-merging payment.conf
CONFLICT (add/add): Merge conflict in payment.conf
error: could not apply 11fa2d8... Add mobile-wallet payment method
…
# (edit payment.conf: keep "mobile-wallet" AND "min_amount = 20")
$ git add payment.conf
$ git rebase --continue
[detached HEAD a1f5d64] Add mobile-wallet payment method
 1 file changed, 1 insertion(+), 1 deletion(-)
Successfully rebased and updated refs/heads/feature/wallet.
$ git log --oneline --graph -4
* a1f5d64 Add mobile-wallet payment method
* 4218834 Set minimum wallet payment
* e90c3b7 Add mobile wallet payment
* 41edf81 Describe the shop in README
$ git push
To ../server/bazar.git
   4218834..a1f5d64  feature/wallet -> feature/wallet

// --force vs --force-with-lease vs --force-if-includes on one shared branch.
// W = Rahim's first commit, N = Nasrin's commit on top of W, W2 = Rahim's amended W.
const parents = { base: [], W: ["base"], N: ["W"], W2: ["base"] };
const reach = c => [c, ...parents[c].flatMap(reach)];   // c and all its ancestors
function scenario(title, fetched, mode) {
  const server = { branch: "N" };                       // Nasrin already pushed N
  const rahim = { branch: "W2", tracking: "W", reflog: ["W", "W2"] };
  if (fetched) rahim.tracking = server.branch;          // e.g. an editor's background fetch
  let result = "pushed";
  if (mode !== "force" && server.branch !== rahim.tracking)
    result = "rejected (stale info)";                   // lease: server must match my tracking ref
  else if (mode === "if-includes" && !rahim.reflog.includes(rahim.tracking))
    result = "rejected (remote ref updated since checkout)";
  if (result === "pushed") server.branch = rahim.branch;
  const kept = reach(server.branch).includes("N") ? "N kept" : "N LOST";
  console.log(title.padEnd(42) + result.padEnd(46) + "server=" + server.branch.padEnd(3) + kept);
}
scenario("stale, --force", false, "force");
scenario("stale, --force-with-lease", false, "lease");
scenario("after fetch, --force-with-lease", true, "lease");
scenario("after fetch, lease + --force-if-includes", true, "if-includes");

$ ssh-keygen -t ed25519 -C "rahim@example.com" -f keys/id_ed25519 -N ""
Generating public/private ed25519 key pair.
Your identification has been saved in keys/id_ed25519
Your public key has been saved in keys/id_ed25519.pub
The key fingerprint is:
SHA256:… rahim@example.com
The key's randomart image is:
…
$ ls keys
id_ed25519
id_ed25519.pub

# ~/.ssh/config
Host github-work
    HostName github.com
    User git
    IdentityFile ~/.ssh/id_ed25519_work
    IdentitiesOnly yes

# then use the alias in the remote URL:
#   git remote set-url origin git@github-work:example/bazar-app.git

$ git remote add upstream https://github.com/example/bazar-app.git
$ git remote -v
origin	../server/bazar.git (fetch)
origin	../server/bazar.git (push)
upstream	https://github.com/example/bazar-app.git (fetch)
upstream	https://github.com/example/bazar-app.git (push)
$ git remote rename upstream example
$ git remote set-url example git@github.com:example/bazar-app.git
$ git remote -v
example	git@github.com:example/bazar-app.git (fetch)
example	git@github.com:example/bazar-app.git (push)
origin	../server/bazar.git (fetch)
origin	../server/bazar.git (push)
$ git remote remove example
$ git remote
origin
$ git remote show origin
* remote origin
  Fetch URL: ../server/bazar.git
  Push  URL: ../server/bazar.git
  HEAD branch: main
  Remote branches:
    feature/coupon tracked
    main           tracked
  Local branches configured for 'git pull':
    feature/coupon merges with remote feature/coupon
    main           merges with remote main
  Local refs configured for 'git push':
    feature/coupon pushes to feature/coupon (up to date)
    main           pushes to main           (up to date)

# commands only; example URLs, not run against a real server
git clone https://github.com/you/bazar-app.git        # your fork  = origin
cd bazar-app
git remote add upstream https://github.com/example/bazar-app.git
git fetch upstream                                     # read the original
git switch -c fix/typo upstream/main                   # start from its latest main
# ... commit ...
git push -u origin fix/typo                            # push to YOUR fork, then open a PR