docs: Record V1.2.6 in Script A's history and add the release note

Script A: header to V1.2.6; entries for blanton_fdr.sh, the unused
lanes off in Script A, and the FDR hooks in Script A, B and C, with
notes on the unverified STOp keyword, the lanes never being turned
back on, the both-units-only gating and the exec bits.

CLAUDE.md / ARCHITECTURE.md: status and release to V1.2.6, FDR and the
unused lanes in the overview, the Script A flow, the tree and the
commands.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0131orciRKrejchsuDk6UpXk

ARCHITECTURE.md

@@ -207,6 +207,7 @@ Blanton_TTL_Script/
             ├── blanton_ber.sh             # 全機 SerDes BER 掃描（phydiag prbs / prbsstat）
             │                              #   V1.2.2 起含 port 268（100G ce0），summary 每 unit 分 200G/100G/TOTAL
             ├── blanton_ber_debug.sh       # BER 原始輸出（p=p31、sleep 40、-u 0|1），不判定
+            ├── blanton_fdr.sh             # FDR 統計（phydiag fdrstat start/clear/Counters/STOp），A/B/C 夾住流量
             ├── bcm_100g_dsc_cycle.sh      # 100G link down/up 循環 + 每輪 DSC 與 retimer TX/RX 讀回（未驗證）
             ├── bcm_dsc_scan.sh            # 全機 SerDes DSC dump（phydiag <port> dsc，~445 port × 2 unit）
             │                              #   由 EN_TX_FIR 控制，A 與 C 各掃一次；單次約 10 分鐘
@@ -387,7 +388,7 @@ PROFILE_CHANNELS=( "0:high:8" "1:low:8" ... )   # "channel:operation:change_perc
 
 | 模組 | 進入點 | 功能 |
 |------|--------|------|
-| **Script A（Pre-test）** | `1_Blanton_Script_A.ttl` V1.2.5 | root 登入 → `date -s` 對時 → 清 job log → **收掉前一輪殘留**（`hw-test-session finish` → `bgctl reset --yes` → `bgctl stop --all` → `bgctl list` 確認清空）→ `hw-test-session start` → **設定風扇轉速** → **等資料面就緒**（`wait_init.ttl`）→ DUT 清單（boot/version/fwutil/syseeprom/ssdhealth/TPM/NVMe）→ BMC enroll + version/status → source bash 工具 → 清/讀 7 組 PCIe AER + `ras-mc-ctl --summary` → `lspci` → margin → PMON → dmesg → **10G/1G 管理網路 ping** → **NFC 基線**（start → 30s → stop → report）→ 100G uplink 設定與狀態 → **BER 基線掃描**（依 `SWB_UNIT`，V1.2.1 新增）→ **一輪流量基線** → **SerDes DSC 基線**（`EN_TX_FIR`）→ `show uptime` |
+| **Script A（Pre-test）** | `1_Blanton_Script_A.ttl` V1.2.6 | root 登入 → `date -s` 對時 → 清 job log → **收掉前一輪殘留**（`hw-test-session finish` → `bgctl reset --yes` → `bgctl stop --all` → `bgctl list` 確認清空）→ `hw-test-session start` → **設定風扇轉速** → **等資料面就緒**（`wait_init.ttl`）→ DUT 清單（boot/version/fwutil/syseeprom/ssdhealth/TPM/NVMe）→ BMC enroll + version/status → source bash 工具 → 清/讀 7 組 PCIe AER + `ras-mc-ctl --summary` → `lspci` → margin → PMON → dmesg → **10G/1G 管理網路 ping** → **NFC 基線**（start → 30s → stop → report）→ 100G uplink 設定與狀態 → **`unused_lanes.sh off`**（V1.2.6）→ **BER 基線掃描**（依 `SWB_UNIT`，V1.2.1 新增）→ **一輪流量基線**（V1.2.6 起兩 unit 時夾 FDR，sleep 40） → **SerDes DSC 基線**（`EN_TX_FIR`）→ `show uptime` |
 | **Script B（Stress）** | `2_Blanton_Script_B.ttl` | **V1.1.8 起 `mlucas-avx2 -cpu 0:15` 由 `systemd-run --unit=mlucas-amm`（`Type=exec`、`Restart=always`）啟動，不再是 shell 的 `&` 背景 job** + `bgctl run` 的 `memtester` / SSD / USB 壓力（v1.1.7 起 SSD/USB 的 `--runtime`/`--passes` 讀 `config.ttl` 的 `SSD_RUNTIME`/`SSD_COUNT`、`USB_RUNTIME`/`USB_COUNT`；BMC memtester 不帶次數 = 跑到被停） + BMC DDR（`bmc-manager run memtester`）→ BMC USB net test（探測 cdc_ncm 介面，`systemd-run` 掛 `BMC_USB_RUNTIME` 秒的 ping，V1.1.8 前寫死 4 小時）→ 啟動 mgmt ping 監控 → **啟動 NFC 輪詢** → `jobs` / `systemctl is-active mlucas-amm` / `bgctl list` → traffic（依 `SWB_UNIT`）→ `while 1` 每輪 PMON + `bgctl list`/`jobs`/`systemctl is-active mlucas-amm` + `sleep 60`（**V1.1.4 起 margin 不在迴圈內**；V1.2.0 起等待走 DUT 端 `sleep` 而非 macro 端 `pause`）|
 | **Script C（Post-test）** | `3_Blanton_Script_C.ttl` | `kill $(jobs -p)` + **`systemctl stop mlucas-amm`**（systemd unit 不是 shell job，`jobs -p` 抓不到）+ `bgctl stop --all` / `reset` + 停 BMC USB unit、mgmt ping 與 **NFC 輪詢** → PMON + dmesg → 7 組 AER + `ras-mc-ctl` → BMC USB `journalctl` **寫進 `log/bmc_usb_net.log`**（不再印在 console） → `ip -s link show eth0/eth1` → `cat` mlucas log（並 `cp` 進 job 目錄一起帶走）→ **NFC `report`** → traffic `stop` + `report` → **SerDes DSC 收尾**（`EN_TX_FIR`）→ **BER 掃描**（依 `SWB_UNIT`）→ NVMe 健康 → `show reboot-cause` → **margin 掃描**（`EN_Margin`，V1.1.4 由 Script B 移來）→ `uptime` → **job log 複製到 USB（帶時戳）** → `exit` + wait『Script done』→ `hw-test-session finish` |
 | **Script 4（Thermal / Safety）** | `4_Blanton_Script_thermal_safety.ttl` | **獨立腳本，不接 A→B→C。** Script A 式的環境建立（登入 / session / 風扇 / `wait_init` / DUT 清單 / BMC / PCIe 清除 / `pcie_bus` / PMON / dmesg）→ **滿載**（`mlucas-avx2 -cpu 0:15`，V1.1.8 起與 Script B 同樣掛成 `mlucas-amm` systemd unit + `blanton_tr518.sh start`）→ `while 1`：PMON + `TH6_SWB0/1_power_readback.sh` + `avt_pmpower.sh`（CPU 封裝功耗，V1.2.3）+ `bgctl list` / `jobs` / `systemctl is-active mlucas-amm`，`pause 60`。**沒有收尾段** —— 中斷後 DUT 仍在 `port cd lb=mac` / `l2 learn off` / `test mode nr=yes`，且 CPU 仍滿載，要手動 `blanton_tr518.sh stop` + `systemctl stop mlucas-amm` |
@@ -818,7 +819,7 @@ margin status、全部 VRM 軌的 Vin/Vout/Iout/Temp、CB + ICB 溫感讀值，
 - [ ] `CHANGELOG.md`：延續三支腳本頂端的 Version History，集中成一份
 - [ ] 三支腳本的 header 版號與 `CHANGELOG.md` 對齊，`config.ttl` 加 `script_version` 並寫進 log 開頭
 - [ ] `docs/TTL_Script_Blanton_Status_*.xlsx` 更新為全 OK，或把剩餘項目移進 Future Extensions
-- [x] 打 git tag，push `nas` + `gitea`（已至 `V1.2.5`；`publish/` 依 Script A 檔頭版號打包）
+- [x] 打 git tag，push `nas` + `gitea`（已至 `V1.2.6`；`publish/` 依 Script A 檔頭版號打包）
 
 **驗收條件：** 從 zip 解壓到一台乾淨的測試 NB，照 README 操作，不看原始碼就能完成一輪 A→B→C
 並產出 summary；`publish/` 內容與 git tag 一致。

CLAUDE.md

@@ -9,7 +9,7 @@ DUT 端的取數能力由一組 **bash 工具庫** 提供（CB FPGA `pcimem` →
 
 完整架構見 [ARCHITECTURE.md](ARCHITECTURE.md)。
 
-**目前狀態（2026-10-21）**：Script A 為 **V1.2.5**（A 集中記錄所有 TTL 的變更）。涵蓋
+**目前狀態（2026-10-21）**：Script A 為 **V1.2.6**（A 集中記錄所有 TTL 的變更）。涵蓋
 PCIe AER / DDR EDAC / PMON+TPM / 電壓 margin（9 顆 LTC2980）/ SWB loopback 線速流量 /
 10G+1G 管理網路 ping / BMC DDR 與 USB / NVMe 健康，壓力層走平台的 `bgctl`。
 switch unit 數量由 `config.ttl` 的 `SWB_UNIT0` / `SWB_UNIT1` 宣告，風扇轉速由 `FAN_SPEED` 指定
@@ -43,11 +43,14 @@ NFC tag 讀取由 `nfc_polling.sh` 背景輪詢（A 做基線、B 起、C 停並
 ⚠️ Script 4 迴圈原本就自己讀一次，現在**每輪讀兩次**。V1.2.5 另有 `blanton_ber_debug.sh`（BER 原始輸出、`p=p31`、`sleep 40`）、
 `retimer_lanes.sh` / `unused_lanes.sh`（把沒接線的 retimer lane / TH6 port 關 TX），以及
 `5_1_Blanton_Script_Boot_Cycle_Fast.ttl`（Script 5 拿掉流量那段，只留 `ps`）。
+**V1.2.6 起 FDR 統計（`blanton_fdr.sh`，`phydiag fdrstat`）接進流量**：A 包住流量基線（sleep 15→40）、
+B 在 soak 前 start、C 收尾 rdcnt + stop，**只在兩個 unit 都開時才跑**。Script A 另在 BER 前先 `unused_lanes.sh off`，
+⚠️ **沒有任何地方再 `on` 回來**。
 以及 **`5_Blanton_Script_Boot_Cycle.ttl`**（重開機循環，**獨立跑不接 A→B→C**：登入 → 風扇 →
 Check Pt1~Pt13 → `reboot` → `wait "Booting in blind mode"`，`cnt_cycle` 每輪遞增，`while 1` 無止境，
 要停就關 Tera Term 的 macro）。**尚未上機驗證**。
 流程圖：`docs/Blanton_Test_Flow.drawio`。
-最後一次發布是 **V1.2.5**；SWB 的 I2C 通道與位址已於 2026-08-19 上機驗證。
+最後一次發布是 **V1.2.6**；SWB 的 I2C 通道與位址已於 2026-08-19 上機驗證。
 margin 的 `VNOM` 已於 2026-08-30 改為 Blanton 實測中位數（144 條軌中 86 條上調 0.8~2.5%）。
 交付用 `./publish/publish.sh` 打包。
 
@@ -188,7 +191,14 @@ sleep 30                                      # 至少等一個 interval 再 rep
 #   清單同 tools/BER_Test.txt，不含 268；BER_PORTS="...,268" 可加
 #   ⚠️ 這支是 p=p31（已上機驗證），blanton_ber.sh 仍是 p=3 —— 兩者量的碼型可能不同
 
-# ── 沒接線的 retimer lane / TH6 port 關 TX（V1.2.5，TTL 未接）──
+# ── FDR 統計（V1.2.6，A/B/C 已接，只在 SWB_UNIT0=SWB_UNIT1=1）──
+~/Blanton_Script/blanton_fdr.sh start          # fdrstat STArt bin_group=both Interval=30，unit 0 → 1
+~/Blanton_Script/blanton_fdr.sh clear          # fdrstat clear
+~/Blanton_Script/blanton_fdr.sh rdcnt          # fdrstat Counters（Interval 結算後才讀，A 用 sleep 40）
+~/Blanton_Script/blanton_fdr.sh stop           # fdrstat STOp ⚠️ 關鍵字是類推的，未上機驗證
+#   -u 0|1 單邊；-i <sec> 改 Interval；-n dry-run。ports 預設 '1-259,270-565'（FDR_PORTS 可改）
+
+# ── 沒接線的 retimer lane / TH6 port 關 TX（V1.2.5；V1.2.6 起 Script A 會 off，沒人 on 回來）──
 ./Blanton_Script/unused_lanes.sh status                 # 兩 unit 全部列出 rx_lock / tx_off
 ./Blanton_Script/unused_lanes.sh off [--asic 0] [--th6] # 預設 TX squelch；--th6 連 retimer 後面的 TH6 port 一起關
 ./Blanton_Script/unused_lanes.sh on

docs/release-notes/v1.2.6.md

@@ -0,0 +1,46 @@
+# v1.2.6 — FDR statistics around the traffic run, and unused lanes turned off before the baseline
+
+## ✨ New features
+
+**`blanton_fdr.sh` — FDR statistics through `phydiag fdrstat`**
+* Four sub-commands, each run on unit 0 then unit 1, over ports `'1-259,270-565'`:
+  `start` (`fdrstat STArt bin_group=both Interval=30`), `clear` (`fdrstat clear`), `rdcnt` (`fdrstat Counters`), `stop` (`fdrstat STOp`).
+* Output is printed as is, under a `### [time] unit N: ...` header — no parsing, no PASS/FAIL.
+* `-u 0` / `-u 1` for one switch unit, `-i <sec>` for the interval, `-n` for a dry run. `FDR_PORTS` overrides the port list.
+
+**FDR runs alongside the traffic test in Script A, B and C**
+* **Script A** wraps its traffic baseline: `fdr start` after `init`, `fdr clear` after `clear`, `fdr rdcnt` after the run, `fdr stop` after the traffic stop. The traffic run is now **40 s instead of 15 s**, so the counters are read after the first 30 s interval has been published — the same rule as `prbsstat Ber`.
+* **Script B** starts and clears FDR with the traffic setup, before the soak loop — the counters run for the whole soak.
+* **Script C** reads them (`rdcnt`) before stopping the traffic and stops FDR after it — the closing read of the counters Script B started.
+
+**Script A turns off the unused lanes before the BER baseline**
+* `unused_lanes.sh off` — TX squelch on the unused retimer lanes and TSC31 (`cd112-cd115`) disabled on the TH6, on both switch boards.
+
+## 📦 Downloads
+
+| File | Contents |
+|---|---|
+| `Script_ABC_Blanton_V1.2.6.zip` | The full Tera Term working directory, including `Blanton_Script/` to copy onto the DUT |
+
+```bash
+chmod +x ~/Blanton_Script/*.sh
+grep -rlU $'\r' ~/Blanton_Script    # expect no output
+```
+
+## ⚠️ Before you run
+
+* **`chmod +x` after deploying.** `blanton_fdr.sh`, `unused_lanes.sh` and `retimer_lanes.sh` are all called by path; `unused_lanes.sh` also refuses to start if `retimer_lanes.sh` is not executable.
+* **`blanton_fdr.sh stop` sends `fdrstat STOp` — that keyword is inferred from `prbsstat STOp` and has not been checked on the bench.** `bcmcmd` exits 0 even when the BCM shell rejects a command, so if it is wrong, FDR keeps running and only the log shows it. Check the first run.
+* **FDR only runs when both switch units are enabled** (`SWB_UNIT0 = SWB_UNIT1 = 1`). The single-unit branches have no FDR, and Script A's single-unit traffic run is still 15 s.
+* **Nothing turns the unused lanes back on.** Script C has no `unused_lanes.sh on`; run it by hand when the DUT is needed in its normal state. Whether a reboot clears it has not been checked.
+* **`unused_lanes.sh off` is not gated by `SWB_UNIT0` / `SWB_UNIT1`** — it always acts on both boards.
+* **`blanton_ber.sh` (Script A / C) still uses `p=3` and `sleep 30`**; see v1.2.5.
+* **Script 4 has no teardown**: finish it with `blanton_tr518.sh stop` **and** `systemctl stop mlucas-amm`.
+* **`FAN_SPEED` is 100.**
+
+## 🔗 Links
+
+* [ARCHITECTURE.md](https://etgit.et-wen.com/etwen/Blanton_TTL_Script/src/branch/main/ARCHITECTURE.md) — test flow, data models, constraints
+* [CLAUDE.md](https://etgit.et-wen.com/etwen/Blanton_TTL_Script/src/branch/main/CLAUDE.md) — commands and the bench gotchas
+
+**Full changelog:** [V1.2.5...V1.2.6](https://etgit.et-wen.com/etwen/Blanton_TTL_Script/compare/V1.2.5...V1.2.6)

src/Script_ABC_Blanton/1_Blanton_Script_A.ttl

@@ -1,6 +1,6 @@
 ; =============================================================================
 ; Script A for Blanton
-; Version : V1.2.5
+; Version : V1.2.6
 ; Date    : 2026-10-21
 ; Author  : ETWen
 ; =============================================================================
@@ -848,6 +848,35 @@
 ;                                                                            same as Script 5
 ;                       tools/BER_Test.txt                              p=3 -> p=p31; add a unit 1 block, a both-units block and
 ;                                                                         port en=0 / en=1 for all cabled ports on each unit
+;   V1.2.6  2026-10-21  Blanton_Script/blanton_fdr.sh                   Created v1.0.0 - FDR statistics through phydiag fdrstat
+;                                                                         start / clear / rdcnt / stop on ports '1-259,270-565':
+;                                                                         fdrstat STArt bin_group=both Interval=30 / clear / Counters /
+;                                                                         STOp. bcmcmd output printed as is, no parsing or PASS/FAIL
+;                                                                         -u 0 / -u 1 (default both), -i <sec> Interval, -n dry run
+;                                                                         !! 'stop' sends 'fdrstat STOp', by analogy with prbsstat STOp
+;                                                                            - NOT verified on the bench. If the BCM shell rejects it,
+;                                                                            FDR keeps running and only the log shows it (bcmcmd exits 0)
+;                                                                         !! called by path - chmod +x ~/Blanton_Script/*.sh
+;                       ScriptA                                         Turn off unused lanes before the BER baseline
+;                                                                         unused_lanes.sh off - both units, TX squelch on the unused
+;                                                                         retimer lanes and TSC31 (cd112-cd115) disabled on the TH6
+;                                                                         !! nothing turns them back on: no 'unused_lanes.sh on' in
+;                                                                            Script C. They stay off until 'unused_lanes.sh on' is run
+;                                                                            by hand (whether a reboot clears them is not checked)
+;                                                                         !! not gated by SWB_UNIT0 / SWB_UNIT1 - always both units
+;                                                                         !! needs the exec bit on unused_lanes.sh AND retimer_lanes.sh
+;                       ScriptA                                         FDR around the traffic baseline (SWB_UNIT0 = SWB_UNIT1 = 1 only)
+;                                                                         init -> fdr start -> clear -> fdr clear -> ... -> start ->
+;                                                                         sleep 40 -> fdr rdcnt -> traffic stop -> fdr stop -> report
+;                                                                         Traffic sleep 15 -> 40 so rdcnt reads after the first 30 s
+;                                                                         Interval is published (same rule as prbsstat Ber)
+;                                                                         !! the single-unit branches have no FDR and still sleep 15
+;                       ScriptB                                         fdr start + fdr clear with the traffic setup, before the loop
+;                                                                         (SWB_UNIT0 = SWB_UNIT1 = 1 only) - the counters run for the
+;                                                                         whole soak
+;                       ScriptC                                         fdr rdcnt before traffic stop, fdr stop after it
+;                                                                         (SWB_UNIT0 = SWB_UNIT1 = 1 only) - the closing read of the
+;                                                                         counters Script B started, bracketing the soak
 ; =============================================================================
 include "config.ttl"
 
@@ -1061,6 +1090,10 @@ sendln "config feature state lldp disabled"
 wait prompt_sonic_root
 sendln "config save -y"
 
+; ========== Turn off unused lanes ==========
+wait prompt_sonic_root
+sendln "~/Blanton_Script/unused_lanes.sh off"
+
 ; ========== BER ==========
 ; Baseline sweep, taken BEFORE the traffic run - ScriptC takes the closing
 ; one after its traffic report, so the pair brackets the soak.
@@ -1117,18 +1150,26 @@ if SWB_UNIT0 = 1 && SWB_UNIT1 = 1 then
     wait prompt_sonic_root
     sendln "blanton_traffic_linespeed init"
     wait prompt_sonic_root
+    sendln "~/Blanton_Script/blanton_fdr.sh start"
+    wait prompt_sonic_root
     sendln "blanton_traffic_linespeed clear"
     wait prompt_sonic_root
+    sendln "~/Blanton_Script/blanton_fdr.sh clear"
+    wait prompt_sonic_root
     sendln "sleep 5"
     wait prompt_sonic_root
     sendln "blanton_traffic_linespeed show"
     wait prompt_sonic_root
     sendln "blanton_traffic_linespeed start"
     wait prompt_sonic_root
-    sendln "sleep 15"
+    sendln "sleep 40"
+    wait prompt_sonic_root
+    sendln "~/Blanton_Script/blanton_fdr.sh rdcnt"
     wait prompt_sonic_root
     sendln "blanton_traffic_linespeed stop"
     wait prompt_sonic_root
+    sendln "~/Blanton_Script/blanton_fdr.sh stop"
+    wait prompt_sonic_root
     sendln "blanton_traffic_linespeed report"
 elseif SWB_UNIT0 = 1 && SWB_UNIT1 = 0 then
     wait prompt_sonic_root

src/Script_ABC_Blanton/2_Blanton_Script_B.ttl

@@ -138,8 +138,12 @@ if SWB_UNIT0 = 1 && SWB_UNIT1 = 1 then
     wait prompt_sonic_root
     sendln "blanton_traffic_linespeed init"
     wait prompt_sonic_root
+    sendln "~/Blanton_Script/blanton_fdr.sh start"
+    wait prompt_sonic_root
     sendln "blanton_traffic_linespeed clear"
     wait prompt_sonic_root
+    sendln "~/Blanton_Script/blanton_fdr.sh clear"
+    wait prompt_sonic_root
     sendln "sleep 5"
     wait prompt_sonic_root
     sendln "blanton_traffic_linespeed show"

src/Script_ABC_Blanton/3_Blanton_Script_C.ttl

@@ -85,9 +85,13 @@ sendln "show interfaces status Ethernet513,Ethernet514"
 
 ; ========== CHECK Traffic counters ==========
 if SWB_UNIT0 = 1 && SWB_UNIT1 = 1 then
+    wait prompt_sonic_root
+    sendln "~/Blanton_Script/blanton_fdr.sh rdcnt"
     wait prompt_sonic_root
     sendln "blanton_traffic_linespeed stop"
     wait prompt_sonic_root
+    sendln "~/Blanton_Script/blanton_fdr.sh stop"
+    wait prompt_sonic_root
     sendln "blanton_traffic_linespeed report"
 elseif SWB_UNIT0 = 1 && SWB_UNIT1 = 0 then
     wait prompt_sonic_root

src/Script_ABC_Blanton/Blanton_Script/blanton_fdr.sh

@@ -0,0 +1,98 @@
+#!/usr/bin/env bash
+# =============================================================================
+# blanton_fdr.sh  --  SerDes FDR statistics (phydiag fdrstat), raw output
+# =============================================================================
+# Version History:
+#   V1.0.0  2026-10-21  First version. start / clear / rdcnt / stop over
+#                       'phydiag <ports> fdrstat ...' through bcmcmd, the same
+#                       way blanton_ber_debug.sh drives prbsstat. Every bcmcmd
+#                       output is printed as is -- no parsing, no PASS/FAIL.
+#
+# Sub-commands (each one runs on unit 0, then unit 1):
+#     start   phydiag '<ports>' fdrstat STArt bin_group=both Interval=30
+#     clear   phydiag '<ports>' fdrstat clear
+#     rdcnt   phydiag '<ports>' fdrstat Counters
+#     stop    phydiag '<ports>' fdrstat STOp
+#
+# ⚠️ 'stop' sends 'fdrstat STOp', by analogy with 'prbsstat STOp'. It has
+#    not been checked on the bench -- if the BCM shell rejects it, look at
+#    'phydiag help' (or 'fdrstat' with no argument) for the right keyword.
+# ⚠️ bcmcmd exits 0 even when the BCM shell refuses a command, so this
+#    script cannot tell success from failure. Read the output.
+#
+# Usage:
+#   ./blanton_fdr.sh <start|clear|rdcnt|stop> [-u 0|1] [-i <sec>] [-n]
+#     -u 0 | -u 1   one switch unit only (default: both, 0 then 1)
+#     -i <sec>      start: fdrstat Interval (default 30)
+#     -n            dry run: print the bcmcmd lines, do not run them
+#
+# Env overrides:
+#   BCMCMD_CMD=bcmcmd  FDR_PORTS=1-259,270-565  FDR_INTERVAL=30
+#   FDR_BIN_GROUP=both
+# =============================================================================
+
+BCMCMD_CMD="${BCMCMD_CMD:-bcmcmd}"
+FDR_UNITS="0 1"
+FDR_PORTS="${FDR_PORTS:-1-259,270-565}"
+FDR_INTERVAL="${FDR_INTERVAL:-30}"
+FDR_BIN_GROUP="${FDR_BIN_GROUP:-both}"
+FDR_DRY_RUN=0
+
+usage() {
+    sed -n '/^# Usage:/,/^# =====/p' "$0" | sed '$d; s/^# \{0,1\}//'
+}
+
+[ $# -ge 1 ] || { usage >&2; exit 2; }
+ACT=$1; shift
+case "$ACT" in
+    start|clear|rdcnt|stop) ;;
+    -h|--help|help) usage; exit 0 ;;
+    *) echo "[ERR ] unknown sub-command '$ACT'" >&2; usage >&2; exit 2 ;;
+esac
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        -u|--unit)
+            case "$2" in
+                0|1) FDR_UNITS="$2" ;;
+                *)   echo "[ERR ] invalid unit '$2' (use 0 or 1)" >&2; exit 2 ;;
+            esac
+            shift 2 ;;
+        -i|--interval)
+            case "$2" in
+                ''|*[!0-9]*) echo "[ERR ] invalid interval '$2'" >&2; exit 2 ;;
+                *) FDR_INTERVAL="$2" ;;
+            esac
+            shift 2 ;;
+        -n|--dry-run) FDR_DRY_RUN=1; shift ;;
+        -h|--help) usage; exit 0 ;;
+        *) echo "[ERR ] unknown option '$1'" >&2; usage >&2; exit 2 ;;
+    esac
+done
+
+# bcmcmd reads stdin -- keep it on /dev/null (see blanton_traffic_linespeed.sh V0.3.1)
+_bcm() {
+    local unit="$1"; shift
+    local cmd="dsh -c \"phydiag '${FDR_PORTS}' fdrstat $*\""
+    echo
+    echo "### [$(date '+%F %T')] unit $unit: phydiag '${FDR_PORTS}' fdrstat $*"
+    if [ "$FDR_DRY_RUN" = "1" ]; then
+        echo "[DRY ] $BCMCMD_CMD -n $unit -c ' ${cmd} '"
+        return 0
+    fi
+    "$BCMCMD_CMD" -n "$unit" -c " ${cmd} " </dev/null 2>&1
+}
+
+case "$ACT" in
+    start) SUB="STArt bin_group=${FDR_BIN_GROUP} Interval=${FDR_INTERVAL}" ;;
+    clear) SUB="clear" ;;
+    rdcnt) SUB="Counters" ;;
+    stop)  SUB="STOp" ;;
+esac
+
+for u in $FDR_UNITS; do
+    _bcm "$u" "$SUB"
+done
+
+echo
+echo "### [$(date '+%F %T')] FDR_${ACT^^}_DONE units: $FDR_UNITS"