From 94a77360bf8687d26c5f4598f219e0accb67248e Mon Sep 17 00:00:00 2001
From: Chris Iverach-Brereton <civerachb@clearpathrobotics.com>
Date: Tue, 26 Aug 2025 16:25:15 -0400
Subject: [PATCH 1/3] Add a new section to install & configure the realtime
 linux kernel

---
 clearpath_computer_installer.sh | 38 +++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/clearpath_computer_installer.sh b/clearpath_computer_installer.sh
index 8e3004e..a3fb559 100644
--- a/clearpath_computer_installer.sh
+++ b/clearpath_computer_installer.sh
@@ -404,6 +404,39 @@ step_install_cuda() {
   fi
 }
 
+step_setup_realtime() {
+  # create the realtime group if needed
+  if [ $(getent group realtime) ]; then
+    log_info "realtime group already exists";
+  else
+    log_info "Adding realtime group";
+    sudo addgroup realtime;
+  fi
+  if id -nGz "$(whoami)" | grep -qzxF "realtime"; then
+    log_info "User:$(whoami) is already in realtime group";
+  else
+    log_info "Adding user:$(whoami) to realtime group";
+    sudo usermod -a -G realtime $(whoami);
+  fi
+
+  # install the realtime kernel
+  sudo apt -y install linux-image-realtime
+
+  # configure realtime limits
+  LIMITS="@realtime soft rtprio 99
+    @realtime soft priority 99
+    @realtime soft memlock unlimited
+    @realtime hard rtprio 99
+    @realtime hard priority 99
+    @realtime hard memlock unlimited"
+
+  for limit in ${LIMITS}; do
+    if ! [ -z "$(cat /etc/security/limits.conf) | grep \"$limit\"" ]; then
+      sudo bash -e "cat \"$limit\" >> /etc/security/limits.conf"
+    fi
+  done
+}
+
 log_space
 log_info "Starting Clearpath Robotics Computer Installer"
 log_space
@@ -450,6 +483,11 @@ if [ ! "$EUID" -eq 0 ]; then
   rosdep -q update
   log_done "Updating rosdep"
 
+  prompt_YESno configure_realtime "Would you like to install the realtime linux kernel (recommended)?"
+  if [[ "$configure_realtime" == "y" ]]; then
+    step_setup_realtime
+  fi
+
   # Check if Clearpath folder exists
   if [ -d /etc/clearpath/ ]; then
     log_warn "Clearpath folder exist, skipping"

From ed8302299239f06aa94072cf8e9f44504014289c Mon Sep 17 00:00:00 2001
From: Chris Iverach-Brereton <civerachb@clearpathrobotics.com>
Date: Tue, 26 Aug 2025 16:44:23 -0400
Subject: [PATCH 2/3] Use an explicit array for limits

---
 clearpath_computer_installer.sh | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/clearpath_computer_installer.sh b/clearpath_computer_installer.sh
index a3fb559..d305bd9 100644
--- a/clearpath_computer_installer.sh
+++ b/clearpath_computer_installer.sh
@@ -423,16 +423,16 @@ step_setup_realtime() {
   sudo apt -y install linux-image-realtime
 
   # configure realtime limits
-  LIMITS="@realtime soft rtprio 99
-    @realtime soft priority 99
-    @realtime soft memlock unlimited
-    @realtime hard rtprio 99
-    @realtime hard priority 99
-    @realtime hard memlock unlimited"
-
-  for limit in ${LIMITS}; do
+  declare -a limits=("@realtime soft rtprio 99"
+    "@realtime soft priority 99"
+    "@realtime soft memlock unlimited"
+    "@realtime hard rtprio 99"
+    "@realtime hard priority 99"
+    "@realtime hard memlock unlimited")
+
+  for limit in "${limits[@]}"; do
     if ! [ -z "$(cat /etc/security/limits.conf) | grep \"$limit\"" ]; then
-      sudo bash -e "cat \"$limit\" >> /etc/security/limits.conf"
+      sudo bash -e "echo \"$limit\" >> /etc/security/limits.conf"
     fi
   done
 }

From 390346104341592b3008277edf4bd8d038514e9f Mon Sep 17 00:00:00 2001
From: Chris Iverach-Brereton <civerachb@clearpathrobotics.com>
Date: Tue, 26 Aug 2025 17:17:40 -0400
Subject: [PATCH 3/3] Fix backwards logic

---
 clearpath_computer_installer.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clearpath_computer_installer.sh b/clearpath_computer_installer.sh
index d305bd9..0cc3e3c 100644
--- a/clearpath_computer_installer.sh
+++ b/clearpath_computer_installer.sh
@@ -431,7 +431,7 @@ step_setup_realtime() {
     "@realtime hard memlock unlimited")
 
   for limit in "${limits[@]}"; do
-    if ! [ -z "$(cat /etc/security/limits.conf) | grep \"$limit\"" ]; then
+    if [ -z "$(cat /etc/security/limits.conf) | grep \"$limit\"" ]; then
       sudo bash -e "echo \"$limit\" >> /etc/security/limits.conf"
     fi
   done