Add RUSH_QUIET_MODE environment variable equivalent to --quiet (#5700)

* Initial plan

* Add RUSH_QUIET_MODE environment variable

Co-authored-by: dmichon-msft <26827560+dmichon-msft@users.noreply.github.com>

* Remove erroneous @microsoft/rush-lib change file

Co-authored-by: dmichon-msft <26827560+dmichon-msft@users.noreply.github.com>

* Deduplicate quiet mode handling in install-run-rush; fix reset() method

Co-authored-by: dmichon-msft <26827560+dmichon-msft@users.noreply.github.com>

* Update rush-lib.api.md with quietMode and RUSH_QUIET_MODE API entries

Co-authored-by: dmichon-msft <26827560+dmichon-msft@users.noreply.github.com>

* Fix RUSH_QUIET_MODE position in rush-lib.api.md to match source declaration order

Co-authored-by: dmichon-msft <26827560+dmichon-msft@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: dmichon-msft <26827560+dmichon-msft@users.noreply.github.com>

Author: Copilot

common/changes/@microsoft/rush/add-rush-quiet-mode_2026-03-12-20-51.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@microsoft/rush",
+      "comment": "Add RUSH_QUIET_MODE environment variable that, when set to `1` or `true`, is equivalent to passing `--quiet` for `rush`, `rushx`, and `install-run-rush.ts`",
+      "type": "minor"
+    }
+  ],
+  "packageName": "@microsoft/rush"
+}

common/reviews/api/rush-lib.api.md

@@ -239,6 +239,7 @@ export class EnvironmentConfiguration {
     static parseBooleanEnvironmentVariable(name: string, value: string | undefined): boolean | undefined;
     static get pnpmStorePathOverride(): string | undefined;
     static get pnpmVerifyStoreIntegrity(): boolean | undefined;
+    static get quietMode(): boolean;
     static reset(): void;
     static get rushGlobalFolderOverride(): string | undefined;
     static get rushTempFolderOverride(): string | undefined;
@@ -273,6 +274,7 @@ export const EnvironmentVariableNames: {
     readonly _RUSH_LIB_PATH: "_RUSH_LIB_PATH";
     readonly RUSH_INVOKED_FOLDER: "RUSH_INVOKED_FOLDER";
     readonly RUSH_INVOKED_ARGS: "RUSH_INVOKED_ARGS";
+    readonly RUSH_QUIET_MODE: "RUSH_QUIET_MODE";
 };
 
 // @beta

libraries/rush-lib/src/api/EnvironmentConfiguration.ts

@@ -245,7 +245,14 @@ export const EnvironmentVariableNames = {
    * Other lifecycle scripts should not make assumptions about Rush's command line syntax
    * if Rush did not explicitly pass along command-line parameters to their process.
    */
-  RUSH_INVOKED_ARGS: 'RUSH_INVOKED_ARGS'
+  RUSH_INVOKED_ARGS: 'RUSH_INVOKED_ARGS',
+
+  /**
+   * When set to `1` or `true`, this environment variable is equivalent to passing the `--quiet` flag
+   * to `rush`, `rushx`, and `install-run-rush.ts`. It suppresses informational startup messages
+   * while preserving error output.
+   */
+  RUSH_QUIET_MODE: 'RUSH_QUIET_MODE'
 } as const;
 
 /**
@@ -293,6 +300,8 @@ export class EnvironmentConfiguration {
 
   private static _tarBinaryPath: string | undefined;
 
+  private static _quietMode: boolean = false;
+
   /**
    * If true, the environment configuration has been validated and initialized.
    */
@@ -456,6 +465,15 @@ export class EnvironmentConfiguration {
     return EnvironmentConfiguration._tarBinaryPath;
   }
 
+  /**
+   * If `true`, Rush will suppress informational startup messages, equivalent to passing `--quiet`.
+   * See {@link EnvironmentVariableNames.RUSH_QUIET_MODE}
+   */
+  public static get quietMode(): boolean {
+    EnvironmentConfiguration._ensureValidated();
+    return EnvironmentConfiguration._quietMode;
+  }
+
   /**
    * The front-end RushVersionSelector relies on `RUSH_GLOBAL_FOLDER`, so its value must be read before
    * `EnvironmentConfiguration` is initialized (and actually before the correct version of `EnvironmentConfiguration`
@@ -606,6 +624,20 @@ export class EnvironmentConfiguration {
             break;
           }
 
+          case EnvironmentVariableNames.RUSH_QUIET_MODE: {
+            // Accept both "true"/"false" string values and the standard "1"/"0" values
+            if (value === 'true' || value === 'false') {
+              EnvironmentConfiguration._quietMode = value === 'true';
+            } else {
+              EnvironmentConfiguration._quietMode =
+                EnvironmentConfiguration.parseBooleanEnvironmentVariable(
+                  EnvironmentVariableNames.RUSH_QUIET_MODE,
+                  value
+                ) ?? false;
+            }
+            break;
+          }
+
           case EnvironmentVariableNames.RUSH_PARALLELISM:
           case EnvironmentVariableNames.RUSH_PREVIEW_VERSION:
           case EnvironmentVariableNames.RUSH_VARIANT:
@@ -661,7 +693,9 @@ export class EnvironmentConfiguration {
    */
   public static reset(): void {
     EnvironmentConfiguration._rushTempFolderOverride = undefined;
-
+    EnvironmentConfiguration._quietMode = false;
+    EnvironmentConfiguration._gitBinaryPath = undefined;
+    EnvironmentConfiguration._tarBinaryPath = undefined;
     EnvironmentConfiguration._hasBeenValidated = false;
   }
 

libraries/rush-lib/src/cli/RushCommandLineParser.ts

@@ -63,6 +63,7 @@ import { InitSubspaceAction } from './actions/InitSubspaceAction';
 import { RushAlerts } from '../utilities/RushAlerts';
 import { initializeDotEnv } from '../logic/dotenv';
 import { measureAsyncFn } from '../utilities/performance';
+import { EnvironmentVariableNames } from '../api/EnvironmentConfiguration';
 
 /**
  * Options for `RushCommandLineParser`.
@@ -220,6 +221,12 @@ export class RushCommandLineParser extends CommandLineParser {
       }
     }
 
+    const quietModeValue: string | undefined =
+      process.env[EnvironmentVariableNames.RUSH_QUIET_MODE];
+    if (quietModeValue === '1' || quietModeValue === 'true') {
+      return true;
+    }
+
     return false;
   }
 

libraries/rush-lib/src/cli/RushXCommandLine.ts

@@ -295,6 +295,12 @@ export class RushXCommandLine {
       }
     }
 
+    const quietModeValue: string | undefined =
+      process.env[EnvironmentVariableNames.RUSH_QUIET_MODE];
+    if (quietModeValue === '1' || quietModeValue === 'true') {
+      quiet = true;
+    }
+
     if (!commandName) {
       help = true;
     }

libraries/rush-lib/src/scripts/install-run-rush.ts

@@ -16,6 +16,7 @@ import type { ILogger } from '../utilities/npmrcUtilities';
 
 const PACKAGE_NAME: string = '@microsoft/rush';
 const RUSH_PREVIEW_VERSION: string = 'RUSH_PREVIEW_VERSION';
+const RUSH_QUIET_MODE: string = 'RUSH_QUIET_MODE';
 const INSTALL_RUN_RUSH_LOCKFILE_PATH_VARIABLE: 'INSTALL_RUN_RUSH_LOCKFILE_PATH' =
   'INSTALL_RUN_RUSH_LOCKFILE_PATH';
 
@@ -72,7 +73,9 @@ function _run(): void {
   }
 
   let commandFound: boolean = false;
-  let logger: ILogger = { info: console.log, error: console.error };
+
+  const quietModeEnvValue: string | undefined = process.env[RUSH_QUIET_MODE];
+  let quiet: boolean = quietModeEnvValue === '1' || quietModeEnvValue === 'true';
 
   for (const arg of packageBinArgs) {
     if (arg === '-q' || arg === '--quiet') {
@@ -82,10 +85,7 @@ function _run(): void {
       // To maintain the same user experience, the install-run* scripts pass along this
       // flag but also use it to suppress any diagnostic information normally printed
       // to stdout.
-      logger = {
-        info: () => {},
-        error: console.error
-      };
+      quiet = true;
     } else if (!arg.startsWith('-') || arg === '-h' || arg === '--help') {
       // We either found something that looks like a command (i.e. - doesn't start with a "-"),
       // or we found the -h/--help flag, which can be run without a command
@@ -105,6 +105,10 @@ function _run(): void {
     process.exit(1);
   }
 
+  const logger: ILogger = quiet
+    ? { info: () => {}, error: console.error }
+    : { info: console.log, error: console.error };
+
   runWithErrorAndStatusCode(logger, () => {
     const version: string = _getRushVersion(logger);
     logger.info(`The ${RUSH_JSON_FILENAME} configuration requests Rush version ${version}`);