add install script to curl install OpsLevel cli (#315)

* add install script to curl install OpsLevel cli

* add curl download to README

README.md

@@ -37,6 +37,13 @@
 brew install opslevel/tap/cli
 ```
 
+#### Curl Download
+
+```sh
+# Note: you can also run without `sudo` and move the binary yourself
+curl -sLS https://raw.githubusercontent.com/OpsLevel/cli/main/install.sh | sudo sh
+```
+
 <!--
 #### Deb
 

install.sh

@@ -0,0 +1,81 @@
+#!/bin/bash
+
+# Function to ensure curl is installed
+has_curl() {
+    _=$(which curl)
+    if [ "$?" = "1" ]; then
+        echo "You need curl to use this script."
+        exit 1
+    fi
+}
+
+# Function to determine the architecture
+detect_arch() {
+    case "$(uname -m)" in
+        x86_64)        ARCH=amd64;;
+        aarch64|arm64) ARCH=arm64;;
+        *)         echo "Unsupported architecture"; exit 1;;
+    esac
+    echo "Detected Architecture: $ARCH"
+}
+
+# Function to determine the OS
+detect_os() {
+    case "$(uname -s)" in
+        Linux*)     OS=linux;;
+        Darwin*)    OS=darwin;;
+        CYGWIN*|MSYS*|MINGW32*|MINGW64*|MINGW*) OS=windows;;
+        *)          echo "Unsupported OS"; exit 1;;
+    esac
+    echo "Detected OS: $OS"
+}
+
+# Version of the OpsLevel CLI to install
+get_version() {
+    VERSION=$(curl -sI https://github.com/OpsLevel/cli/releases/latest | grep -i "location:" | awk -F"/" '{ printf "%s", $NF }' | tr -d '\r')
+    if [ ! $VERSION ]; then
+        echo "Failed while attempting to install OpsLevel's cli. Please manually install:"
+        echo ""
+        echo "Open your web browser and go to https://github.com/OpsLevel/cli?tab=readme-ov-file#installation for instructions."
+        exit 1
+    fi
+}
+
+# Function to download and install the CLI tool
+install_cli() {
+    DOWNLOAD_URL="https://github.com/OpsLevel/cli/releases/download/${VERSION}/opslevel-${OS}-${ARCH}.tar.gz"
+
+    # Temporary directory to store the download
+    TMP_DIR=$(mktemp -d)
+
+    echo "Downloading OpsLevel CLI from $DOWNLOAD_URL ..."
+    curl -L -o "$TMP_DIR/opslevel.tar.gz" "$DOWNLOAD_URL"
+
+    if [ $? -ne 0 ]; then
+        echo "Download failed. Please check the version and try again."
+        exit 1
+    fi
+
+    echo "Extracting the OpsLevel CLI..."
+    tar -xzf "$TMP_DIR/opslevel.tar.gz" -C "$TMP_DIR"
+
+    echo "Installing the OpsLevel CLI to /usr/local/bin ..."
+    sudo mv "$TMP_DIR/opslevel" /usr/local/bin/
+
+    if [ $? -ne 0 ]; then
+        echo "Installation failed."
+        exit 1
+    fi
+
+    echo "Cleaning up..."
+    rm -rf "$TMP_DIR"
+
+    echo "OpsLevel CLI installed successfully!"
+}
+
+# Main script execution
+has_curl
+detect_arch
+detect_os
+get_version
+install_cli