Adds warning for conda install without symlink (#442)

# Description

When using conda with binary installation of Isaac Sim, we require first
creating the symlink _isaac_sim before creating the conda environment so
that we can find the source file to set up the conda environment
correctly. This change adds a warning message if we do not detect
_isaac_sim when the conda environment is created as a way to indicate
potential issues for users.


## Type of change

- This change requires a documentation update

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [ ] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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isaaclab.bat

@@ -114,6 +114,17 @@ if errorlevel 1 (
     echo [ERROR] Conda could not be found. Please install conda and try again.
     exit /b 1
 )
+
+rem check if _isaac_sim symlink exists and isaacsim-rl is not installed via pip
+if not exist "%ISAACLAB_PATH%\_isaac_sim" (
+    python -m pip list | findstr /C:"isaacsim-rl" >nul
+    if errorlevel 1 (
+        echo [WARNING] _isaac_sim symlink not found at %ISAACLAB_PATH%\_isaac_sim
+        echo     This warning can be ignored if you plan to install Isaac Sim via pip.
+        echo     If you are using a binary installation of Isaac Sim, please ensure the symlink is created before setting up the conda environment.
+    )
+)
+
 rem check if the environment exists
 call conda env list | findstr /c:"%env_name%" >nul
 if %errorlevel% equ 0 (

isaaclab.sh

@@ -22,6 +22,27 @@ export ISAACLAB_PATH="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && p
 # Helper functions
 #==
 
+# install system dependencies
+install_system_deps() {
+    # check if cmake is already installed
+    if command -v cmake &> /dev/null; then
+        echo "[INFO] cmake is already installed."
+    else
+        # check if running as root
+        if [ "$EUID" -ne 0 ]; then
+            echo "[INFO] Installing system dependencies..."
+            sudo apt-get update && sudo apt-get install -y --no-install-recommends \
+                cmake \
+                build-essential
+        else
+            echo "[INFO] Installing system dependencies..."
+            apt-get update && apt-get install -y --no-install-recommends \
+                cmake \
+                build-essential
+        fi
+    fi
+}
+
 # check if running in docker
 is_docker() {
     [ -f /.dockerenv ] || \
@@ -136,6 +157,13 @@ setup_conda_env() {
         exit 1
     fi
 
+    # check if _isaac_sim symlink exists and isaacsim-rl is not installed via pip
+    if [ ! -L "${ISAACLAB_PATH}/_isaac_sim" ] && ! python -m pip list | grep -q 'isaacsim-rl'; then
+        echo -e "[WARNING] _isaac_sim symlink not found at ${ISAACLAB_PATH}/_isaac_sim"
+        echo -e "\tThis warning can be ignored if you plan to install Isaac Sim via pip."
+        echo -e "\tIf you are using a binary installation of Isaac Sim, please ensure the symlink is created before setting up the conda environment."
+    fi
+
     # check if the environment exists
     if { conda env list | grep -w ${env_name}; } >/dev/null 2>&1; then
         echo -e "[INFO] Conda environment named '${env_name}' already exists."
@@ -273,6 +301,8 @@ while [[ $# -gt 0 ]]; do
     # read the key
     case "$1" in
         -i|--install)
+            # install system dependencies first
+            install_system_deps
             # install the python packages in IsaacLab/source directory
             echo "[INFO] Installing extensions inside the Isaac Lab repository..."
             python_exe=$(extract_python_exe)
@@ -448,7 +478,7 @@ while [[ $# -gt 0 ]]; do
             ;;
         -h|--help)
             print_help
-            exit 1
+            exit 0
             ;;
         *) # unknown option
             echo "[Error] Invalid argument provided: $1"