diff --git a/RunCommand/Linux/Linux_serialLog/Linux_serialLog.sh b/RunCommand/Linux/Linux_serialLog/Linux_serialLog.sh
new file mode 100644
index 0000000..31745d7
--- /dev/null
+++ b/RunCommand/Linux/Linux_serialLog/Linux_serialLog.sh
@@ -0,0 +1,312 @@
+#!/usr/bin/bash
+# -----------------------------------------------------------------------------
+# File: Linux_serialLog.sh
+# This script is designed to modify the 'printk' setting in a running Linux VM
+# to increase or decrease the verbosity of the kernel logging printing to the
+# serial console.
+#
+# The default will be to raise the log to level 7 (debug) in a non-persistent
+# manner to capture as much information as possible. Options are available to
+# specify the log level, as well as to make the changes permanent.
+# -----------------------------------------------------------------------------
+# Version: 1.1.0
+# Released: 2026-09-10
+# Latest update: 2026-09-10
+# Author: Azure Support
+#
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the terms found in the LICENSE file in the root of this source tree.
+# -----------------------------------------------------------------------------
+# -----------------------------------------------------------------------------
+# define this once for the script run - so that all backups have the same exact
+# timestamp
+TIMESTAMP=`date +%Y%m%dT%H%M%S`
+# set an internal reference name - we can't use $0 because RunCommand creates 
+# its payload script using the generic name 'script.sh'
+SCRIPTNAME="Linux_serialLog.sh"
+
+# -----------------------------------------------------------------------------
+# printk / console reporting (runtime, phase 1)
+# -----------------------------------------------------------------------------
+
+# reads /proc/sys/kernel/printk into CUR_LEVEL/DEFAULT_LEVEL/MIN_LEVEL/BOOT_DEFAULT_LEVEL
+function get_printk_levels() {
+  if [[ ! -r /proc/sys/kernel/printk ]]; then
+    echo "ERR: Unable to read /proc/sys/kernel/printk"
+    return 1
+  fi
+  read -r CUR_LEVEL DEFAULT_LEVEL MIN_LEVEL BOOT_DEFAULT_LEVEL < /proc/sys/kernel/printk
+}
+
+# maps a numeric kernel log level (0-7) to its syslog priority name
+function loglevel_name() {
+  local level="$1"
+  case "$level" in
+    0) echo "emerg" ;;
+    1) echo "alert" ;;
+    2) echo "crit" ;;
+    3) echo "err" ;;
+    4) echo "warn" ;;
+    5) echo "notice" ;;
+    6) echo "info" ;;
+    7) echo "debug" ;;
+    *) echo "unknown" ;;
+  esac
+}
+
+function report_printk_levels() {
+  get_printk_levels || return 1
+  echo "PRINTK: current=$CUR_LEVEL($(loglevel_name "$CUR_LEVEL")) default=$DEFAULT_LEVEL($(loglevel_name "$DEFAULT_LEVEL")) minimum=$MIN_LEVEL($(loglevel_name "$MIN_LEVEL")) boot_default=$BOOT_DEFAULT_LEVEL($(loglevel_name "$BOOT_DEFAULT_LEVEL"))"
+}
+
+# reports every registered kernel console output channel and how it is wired up
+# one tagged line per data point - keeps az cli's escaped/flattened JSON output greppable
+function report_console_channels() {
+  if [[ -r /proc/consoles ]]; then
+    while IFS= read -r line; do
+      echo "CONSOLE: $line"
+    done < /proc/consoles
+    echo "CONSOLE_LEGEND: R=accepts kernel input W=receives kernel output U=unblanked (E)=enabled (B)=boot console (p)=preferred console (b)=braille device"
+  else
+    echo "WARN: /proc/consoles not readable"
+  fi
+
+  if [[ -r /sys/class/tty/console/active ]]; then
+    echo "CONSOLE_ACTIVE: $(cat /sys/class/tty/console/active)"
+  else
+    echo "WARN: /sys/class/tty/console/active not readable"
+  fi
+
+  if [[ -r /proc/cmdline ]]; then
+    local cmdline_consoles
+    cmdline_consoles="$(grep -o 'console=[^ ]*' /proc/cmdline | tr '\n' ' ')"
+    echo "CONSOLE_CMDLINE: ${cmdline_consoles:-none}"
+  else
+    echo "WARN: /proc/cmdline not readable"
+  fi
+}
+
+function report_current_state() {
+  echo "REPORT: printk/console state @ ${TIMESTAMP}"
+  report_printk_levels
+  report_console_channels
+}
+
+# -----------------------------------------------------------------------------
+# printk level change (runtime, phase 2 - non-persistent)
+# -----------------------------------------------------------------------------
+
+# writing a single value to /proc/sys/kernel/printk only updates the leading
+# (current) field, leaving default/minimum/boot-default untouched - this
+# works on every distro and kernel version with procfs, no dependency on
+# dmesg/sysctl being installed, making it the most portable option
+function set_printk_level_runtime() {
+  local level="$1"
+
+  if [[ ! "$level" =~ ^[0-7]$ ]]; then
+    echo "ERR: requested level '$level' is invalid - must be 0-7"
+    return 1
+  fi
+
+  if [[ ! -w /proc/sys/kernel/printk ]]; then
+    echo "ERR: /proc/sys/kernel/printk is not writable (must run as root)"
+    return 1
+  fi
+
+  echo "$level" > /proc/sys/kernel/printk
+  echo "SET: runtime (non-persistent) current printk level requested = $level"
+}
+
+# -----------------------------------------------------------------------------
+# printk level change (persistent, phase 3 - survives reboot)
+# -----------------------------------------------------------------------------
+
+# drop-in read by systemd-sysctl.service on every systemd-based distro (RHEL,
+# SLES, Ubuntu/Debian, etc.) - no distro-family branching needed for this part
+SYSCTL_DROPIN="/etc/sysctl.d/01-linux-seriallog-printk.conf"
+
+function set_printk_level_persistent() {
+  local level="$1"
+
+  if [[ ! "$level" =~ ^[0-7]$ ]]; then
+    echo "ERR: requested level '$level' is invalid - must be 0-7"
+    return 1
+  fi
+
+  if [[ ! -d /etc/sysctl.d ]]; then
+    echo "ERR: /etc/sysctl.d does not exist - cannot persist via systemd-sysctl"
+    return 1
+  fi
+
+  if [[ -e "$SYSCTL_DROPIN" ]]; then
+    cp -p "$SYSCTL_DROPIN" "${SYSCTL_DROPIN}.bak.${TIMESTAMP}"
+    echo "INFO: backed up existing $SYSCTL_DROPIN to ${SYSCTL_DROPIN}.bak.${TIMESTAMP}"
+  fi
+
+  cat > "$SYSCTL_DROPIN" <<EOF
+# Created by Linux_serialLog.sh (${TIMESTAMP})
+# Sets the printk console log level applied at boot by systemd-sysctl.service
+kernel.printk = ${level}
+EOF
+
+  echo "SET: persistent printk level written to $SYSCTL_DROPIN (applied on next boot by systemd-sysctl.service)"
+
+  if command -v sysctl >/dev/null 2>&1; then
+    if sysctl -p "$SYSCTL_DROPIN" >/dev/null 2>&1; then
+      echo "SET: sysctl -p also applied $SYSCTL_DROPIN immediately"
+    else
+      echo "WARN: sysctl -p failed to apply $SYSCTL_DROPIN immediately - it will still take effect on next boot"
+    fi
+  else
+    echo "WARN: sysctl command not found - drop-in will only take effect on next boot via systemd-sysctl.service"
+  fi
+}
+
+# -----------------------------------------------------------------------------
+# OS family detection (phase 4 prerequisite - RedHat-like distros persist a
+# printk-related kernel cmdline boot parameter via GRUB; SLES and
+# Debian-based distros do not, so no branching is needed for those families)
+# - we won't invent the loglevel kernel cmdline boot parameter for distributions 
+#   that don't already use it normally
+# -----------------------------------------------------------------------------
+
+# reads /etc/os-release into OS_ID/OS_ID_LIKE and sets IS_REDHAT_FAMILY (0/1)
+function detect_os_family() {
+  OS_ID=""
+  OS_ID_LIKE=""
+  IS_REDHAT_FAMILY=0
+
+  if [[ ! -r /etc/os-release ]]; then
+    echo "WARN: /etc/os-release not readable - unable to determine OS family"
+    return 1
+  fi
+
+  # shellcheck disable=SC1091
+  source /etc/os-release
+  OS_ID="${ID:-}"
+  OS_ID_LIKE="${ID_LIKE:-}"
+
+  # ID_LIKE can hold multiple space-separated values (e.g. "rhel fedora")
+  if [[ "$OS_ID" =~ ^(rhel|centos|fedora|rocky|almalinux|ol)$ ]] || [[ " $OS_ID_LIKE " =~ (rhel|fedora) ]]; then
+    IS_REDHAT_FAMILY=1
+  fi
+
+  echo "OS_FAMILY: id=${OS_ID:-unknown} id_like=${OS_ID_LIKE:-none} redhat_family=$([[ $IS_REDHAT_FAMILY -eq 1 ]] && echo yes || echo no)"
+}
+
+# -----------------------------------------------------------------------------
+# GRUB boot parameter update (phase 4b/4c - RedHat-family only)
+# grubby is Red Hat's documented tool for adding/removing kernel command-line
+# parameters (`grubby --update-kernel=ALL --args=...` / `--remove-args=...`),
+# and it transparently handles both legacy grub2 menuentry-based configs
+# (RHEL7-style) and BLS (/boot/loader/entries, RHEL8+) systems - so there is
+# no need to separately hand-edit /etc/default/grub and regenerate grub.cfg
+# via grub2-mkconfig; grubby edits the real, in-effect boot entries for every
+# currently installed kernel directly.
+# -----------------------------------------------------------------------------
+
+# inspects the default boot entry's kernel args for an existing loglevel= via
+# grubby - sets BOOT_LOGLEVEL_CUR; reports and returns 1 when nothing is set,
+# so a missing loglevel= is never introduced (matches the persistent sysctl
+# drop-in's "don't invent a parameter" contract)
+function get_boot_loglevel() {
+  BOOT_LOGLEVEL_CUR=""
+
+  local info
+  info="$(grubby --info=DEFAULT 2>/dev/null)"
+  if [[ -z "$info" ]]; then
+    echo "WARN: grubby --info=DEFAULT returned no output - unable to inspect current boot args"
+    return 1
+  fi
+
+  if [[ "$info" =~ loglevel=([0-9]+) ]]; then
+    BOOT_LOGLEVEL_CUR="${BASH_REMATCH[1]}"
+    echo "INFO: existing boot loglevel found = ${BOOT_LOGLEVEL_CUR}"
+    return 0
+  fi
+
+  echo "INFO: no explicit loglevel= boot parameter set - kernel uses its compiled-in default at boot"
+  return 1
+}
+
+# updates loglevel= across every installed kernel's boot entry via grubby -
+# only called once get_boot_loglevel has confirmed one is already set, so a
+# missing loglevel= is never introduced
+function set_boot_loglevel() {
+  local level="$1"
+
+  if [[ -d /boot/loader/entries ]]; then
+    local entry
+    for entry in /boot/loader/entries/*.conf; do
+      [[ -e "$entry" ]] || continue
+      cp -p "$entry" "${entry}.bak.${TIMESTAMP}"
+    done
+    echo "INFO: backed up existing BLS entries under /boot/loader/entries to *.bak.${TIMESTAMP}"
+  fi
+
+  if grubby --update-kernel=ALL --remove-args="loglevel" --args="loglevel=${level}"; then
+    echo "SET: updated loglevel=${level} across all installed kernels via grubby"
+  else
+    echo "ERR: grubby failed to update loglevel across boot entries"
+    return 1
+  fi
+}
+
+# -----------------------------------------------------------------------------
+# printk level change (persistent boot parameter, phase 4 - RedHat-like only)
+# -----------------------------------------------------------------------------
+
+# RHEL and derived distributions persist a printk-related boot parameter via
+# GRUB that no other distributions set today.  We could make this work for all
+# distros but that could be more expansive.  If others start making loglevel= 
+# directives we will build it.  Updates an existing loglevel= via grubby only
+# - a missing one is never introduced.
+function reset_boot_printk_param() {
+  local level="$1"
+
+  detect_os_family
+
+  if [[ "$IS_REDHAT_FAMILY" -ne 1 ]]; then
+    echo "INFO: boot parameter reset not required for this OS family (id=${OS_ID:-unknown}) - skipping"
+    return 0
+  fi
+
+  if ! command -v grubby >/dev/null 2>&1; then
+    echo "ERR: grubby not found - cannot inspect/update boot loader kernel parameters"
+    return 1
+  fi
+
+  # only update an existing loglevel= - never introduce one that wasn't already there
+  if ! get_boot_loglevel; then
+    echo "INFO: no existing loglevel= boot parameter to update - leaving boot configuration untouched"
+    return 0
+  fi
+
+  set_boot_loglevel "$level"
+}
+
+# -----------------------------------------------------------------------------
+# main
+#   $1 = desired printk level (0-7), optional - defaults to 7 (debug) when omitted
+#   $2 = persist flag - defaults to runtime-only (not persisted) when omitted
+# -----------------------------------------------------------------------------
+REQUESTED_LEVEL="${1:-7}"
+PERSIST_FLAG="${2:-}"
+
+report_current_state
+
+case "${PERSIST_FLAG,,}" in
+  # do not include '1' in the list of accepted values - to avoid confusion with the numeric log level 1 (alert)
+  persist|true|yes) DO_PERSIST=1 ;;
+  *) DO_PERSIST=0 ;;
+esac
+
+echo "REQUEST: change printk level to $REQUESTED_LEVEL (persist=$([[ $DO_PERSIST -eq 1 ]] && echo yes || echo no))"
+
+if set_printk_level_runtime "$REQUESTED_LEVEL"; then
+  if [[ "$DO_PERSIST" -eq 1 ]]; then
+    set_printk_level_persistent "$REQUESTED_LEVEL"
+    reset_boot_printk_param "$REQUESTED_LEVEL"
+  fi
+  report_current_state
+fi
diff --git a/RunCommand/Linux/Linux_serialLog/README.md b/RunCommand/Linux/Linux_serialLog/README.md
new file mode 100644
index 0000000..ad01c2a
--- /dev/null
+++ b/RunCommand/Linux/Linux_serialLog/README.md
@@ -0,0 +1,147 @@
+# Azure VM Kernel Serial Log Verbosity Adjuster (Linux)
+
+This bash script adjusts the kernel `printk` console log level on a running Linux VM, controlling how much kernel logging is written to the linux device configured as 'console' at boot. When configured properly, this is `ttyS0` and connects to the Azure Serial Console available in the Azure portal or through the cli command `az serial-console` ([documentation](https://learn.microsoft.com/en-us/cli/azure/serial-console)) Raising the numeric level (up to `7`/debug) captures far more boot and runtime kernel diagnostics for troubleshooting; lowering it reduces noise.
+
+By default the script sets the level to `7` (debug) in a **non-persistent** (runtime-only) manner, so it can be run as a one-shot diagnostic capture via Azure Run Command without altering the persistent state of the VM. An optional flag makes the change permanent (survives reboot).
+
+## How It Works
+
+The script runs up to 4 phases:
+
+1. **Initial state report** — Reads `/proc/sys/kernel/printk` (current/default/minimum/boot-default levels) and every registered kernel console channel (`/proc/consoles`, `/sys/class/tty/console/active`, `console=` boot cmdline args), printing each with the description of the value.
+2. **Runtime level change** — Writes the requested level to `/proc/sys/kernel/printk`. This only updates the *current* field, leaving default/minimum/boot-default untouched, and takes effect immediately with no reboot required.
+3. **Persistent sysctl drop-in** *(only if the persist flag is set)* — Writes `kernel.printk = <level>` to `/etc/sysctl.d/01-linux-seriallog-printk.conf`, backing up a drop-in from a previous execution first, and applies it immediately via `sysctl -p` if available. This is read by `systemd-sysctl.service` on every boot, on any systemd-based distro.
+4. **Persistent GRUB boot parameter** *(only if the persist flag is set, RedHat-family only)* — Some distributions (RHEL and derivatives) traditionally carry an explicit `loglevel=` kernel boot parameter. If one is already present, the script updates it across every installed kernel via `grubby --update-kernel=ALL`. It never introduces a `loglevel=` parameter on a distro/VM that didn't already have one.
+5. **Final state report** — Re-reads and prints the levels with the same methods as phase 1 so the before/after values can be compared.
+
+## Parameters
+
+The script takes two **positional** parameters — no named/flag parsing is done, since Azure Run Command's `--parameters` strips any `name=` prefix before invoking the script, leaving only bare values passed as `$1`, `$2`, ...
+
+| Position | Meaning | Valid values | Default when omitted |
+|---|---|---|---|
+| `$1` | Desired printk log level | `0`-`7` | `7` (debug) |
+| `$2` | Persist flag | `persist`, `true`, `yes` (case-insensitive) → persistent; anything else → runtime-only | runtime-only (not persisted) |
+
+> **Note:** `1` is deliberately **not** accepted as a persist-flag value, to avoid confusion with the numeric log level `1` (`alert`).
+
+## Persistence Details
+
+| Mechanism | Scope | Applies to |
+|---|---|---|
+| `/proc/sys/kernel/printk` write | Runtime only, lost on reboot | All distros/kernels with procfs |
+| `/etc/sysctl.d/01-linux-seriallog-printk.conf` | Survives reboot via `systemd-sysctl.service` | All systemd-based distros (RHEL, SUSE, Ubuntu/Debian, etc.) |
+| GRUB `loglevel=` boot parameter (via `grubby`) | Survives reboot, affects kernel messages emitted before systemd starts | RedHat-family only (`rhel`, `centos`, `fedora`, `rocky`, `almalinux`, `ol`, or any `ID_LIKE` containing `rhel`/`fedora`) — and only when a `loglevel=` parameter already exists |
+
+SUSE and Debian-based families don't set a `loglevel=` boot parameter by default, so the script intentionally does not insert one there; the sysctl drop-in is the only persistence for those families.
+
+## Supported Distributions
+
+The script attempts [phases 1-3](#how-it-works) unconditionally on any systemd-based Linux — no distro-family branching is needed for the runtime write or the sysctl drop-in. Phase 4 (GRUB boot parameter) is explicitly gated:
+
+| Family | GRUB boot-parameter phase |
+|---|---|
+| Red Hat family (`rhel`, `centos`, `fedora`, `rocky`, `almalinux`, `ol`) | Attempted (requires `grubby`) |
+| SUSE, Debian/Ubuntu, and others | Skipped — reported via an `INFO:` line, not an error |
+
+## Prerequisites
+
+- Root/sudo privileges (required to write `/proc/sys/kernel/printk` and the sysctl drop-in)
+- `systemd` (for the persistent sysctl drop-in to take effect at boot)
+- `sysctl` (optional — applies the persistent value immediately; otherwise it only takes effect on next boot)
+- `grubby` (only required for the persistent GRUB boot-parameter phase on RedHat-family distros)
+
+## Usage
+
+Download the script to the local session. This can be done in `bash` or PowerShell, optionally in the [Azure Cloud Shell](https://shell.azure.com):
+
+```bash
+curl -sL https://aka.ms/rcl-seriallevel -o Linux_serialLog.sh
+```
+
+```PowerShell
+Invoke-WebRequest `
+    -Uri 'https://aka.ms/rcl-seriallevel' -OutFile 'Linux_serialLog.sh'
+```
+
+Run the script via Azure Run Command:
+
+### Azure CLI
+
+Raise verbosity to debug (level 7), runtime-only (default behavior, no parameters needed):
+
+```bash
+az vm run-command invoke \
+    --resource-group <resource-group> \
+    --name <vm-name> \
+    --command-id RunShellScript \
+    --scripts @Linux_serialLog.sh
+```
+
+Set a specific level, runtime-only:
+
+```bash
+az vm run-command invoke \
+    --resource-group <resource-group> \
+    --name <vm-name> \
+    --command-id RunShellScript \
+    --scripts @Linux_serialLog.sh \
+    --parameters 4
+```
+
+Set a specific level and make it persistent (survives reboot):
+
+```bash
+az vm run-command invoke \
+    --resource-group <resource-group> \
+    --name <vm-name> \
+    --command-id RunShellScript \
+    --scripts @Linux_serialLog.sh \
+    --parameters 7 persist
+```
+
+To get more readable output including the exit `code` and `displayStatus` alongside the script's log:
+
+```powershell
+az vm run-command invoke `
+    --resource-group <resource-group> `
+    --name <vm-name> `
+    --command-id RunShellScript `
+    --scripts @Linux_serialLog.sh `
+    --parameters 7 persist `
+    --query "value[].[code, displayStatus, message]" -o tsv
+```
+
+`-o tsv` renders the embedded `\n` characters in `message` as real newlines, so each tagged output line (`REPORT:`, `PRINTK:`, `CONSOLE:`, `SET:`, etc.) prints on its own line.
+
+## Important: Non-Persistent by Default
+
+Unless the persist flag (`$2`) is explicitly set to `persist`, `true`, or `yes`, every change made by this script is **runtime-only**:
+
+- The requested printk level takes effect immediately
+- After the next reboot, the VM reverts to whatever printk level/boot parameters were already configured
+
+## Exit Codes
+
+The script does not define custom exit codes — it exits with the status of the last command it executed. A non-zero exit generally indicates the runtime `printk` write failed (e.g. invalid level, or not running as root), since that failure short-circuits the persistent phases.
+
+## References
+
+- [Azure Serial Console for Linux](https://learn.microsoft.com/troubleshoot/azure/virtual-machines/linux/serial-console-linux)
+- [Kernel command-line parameters (Red Hat)](https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/9/html/managing_monitoring_and_updating_the_kernel/configuring-kernel-command-line-parameters_managing-monitoring-and-updating-the-kernel)
+- [`sysctl.d` directories and drop-ins (systemd)](https://www.freedesktop.org/software/systemd/man/latest/sysctl.d.html)
+- [`printk` kernel documentation](https://www.kernel.org/doc/html/latest/core-api/printk-basics.html)
+- [Azure Run Command overview](https://learn.microsoft.com/azure/virtual-machines/linux/run-command)
+
+## Liability
+
+As described in the [MIT license](../../../LICENSE.txt), these scripts are provided as-is with no warranty or liability associated with their use.
+
+## Provide Feedback
+
+We value your input. If you encounter problems with the scripts or ideas on how they can be improved please file an issue in the [Issues](https://github.com/Azure/azure-support-scripts/issues) section of the project.
+
+## Known Issues
+
+- The GRUB boot-parameter phase only updates an existing `loglevel=` value — it will not add one to a distro/kernel that never had one configured.
+- SUSE and Debian/Ubuntu-family distros do not receive a GRUB boot-parameter update, since they don't set a `loglevel=` parameter by default; the sysctl drop-in is relied upon for those families.