---
title: How to execute complex startup commands using Serverless Jobs
description: Learn how to run complex commands at job run start and scripts using Scaleway Serverless Jobs and Secrets Manager.
tags: run execute start serverless job scaleway script startup secret bash complex command pipe
dates:
  validation: 2025-08-19 
  posted: 2025-08-19
---
import Requirements from '@macros/iam/requirements.mdx'

Scaleway Serverless Jobs allows you to execute specific startup commands when running a job. Due to technical specifications, complex commands (e.g. piped commands, `xargs` commands) may fail occasionally, preventing jobs from running successfully.

You can bypass this limitation by passing complex commands and scripts to a Serverless Job via a [secret reference](/serverless-jobs/concepts/#secrets-reference). You can then inject this secret as a file in your job, and call it at startup to execute the commands it contains.

<Requirements />

- A Scaleway account logged into the [console](https://console.scaleway.com)
- [Owner](/iam/concepts/#owner) status or [IAM permissions](/iam/concepts/#permission) allowing you to perform actions in the intended Organization
- Created a [Serverless Job](/serverless-jobs/how-to/create-job/)

## How to create a secret containing your command

1. Click **Secret Manager** in the **Security & Identity** section of the [Scaleway console](https://console.scaleway.com/) side menu.

2. In the **Region** drop-down, select the [region](/secret-manager/concepts/#region) in which you want to store your secret. Secrets cannot be moved from one region to another after creation.

3. Click **+ Create secret**.

4. Select **Import secret**, choose the **Opaque** secret type, then drag and drop your file to the dedicated area. The maximum file size for your secret is 64 KiB.
    <Message type="note">
    We recommend using a shell script (`.sh`) file containing your command. Refer to the [section below](#complex-commands-examples) for example commands.
    </Message>

5. Choose the **Scaleway-managed encryption key**, as it requires no configuration on your side.

6. Choose a [path](/secret-manager/concepts/#path) for your secret.

7. Enter a name for your secret, and, optionally, add a description and tags.
      
8. Click **Create secret** to confirm.

Your file can now be passed to your Serverless Job as a secret reference.

## Create a Serverless Job referencing your command as a secret

1. Click **Jobs** in the **Serverless** section of the side menu. The jobs page displays.

2. Click **Create job**. The job creation wizard displays.

3. Select the **external** container registry.

4. Enter the following image URL:
    ```bash
    scaleway/cli:latest
    ```

5. Enter a name, select the desired region, and choose the smallest **resources** available.

6. From the **Data** tab, add your command file as a [secrets reference](/serverless-functions/concepts/#secrets). Refer to the [dedicated documentation](/serverless-jobs/how-to/reference-secret-in-job/) on secrets for more information.

7. From the **Execution** tab, add the following startup command to call your file:
    ```bash
    bash /complex_command.sh start
    ```

8. Click **Create job** to finish.

You job is now ready to run.

## Complex commands examples

Below are examples of commands that must be passed via a secret referenced as a file in Serverless Jobs. You can find more complex command examples on the [Scaleway CLI repository](https://github.com/scaleway/scaleway-cli/blob/master/docs/cookbook.md).

**Retrieve a specific field from the output using jq**

```bash
## Retrieve all available instance type names

# Using jq
scw -o json instance server-type list | jq -r '.[].name'
# Using CLI templates
scw instance server-type list -o template="{{ .Name }}"
```

**Filter command output using jq**

```bash
# Retrieve all available instance type with GPUs
scw -o json instance server-type list | jq '.[] | select (.gpu > 0)'
```

**Parallelize actions using xargs**

```bash
## Reboot all listed servers at the same time, 8 max concurrent actions

# Using jq
scw -o json instance server list | jq -r '.[].id' | xargs -L1 -P8 scw instance server reboot
# Using CLI templates
scw instance server list -o template="{{ .ID }}" | xargs -L1 -P8 scw instance server reboot
```

**Create arguments for a CLI command and use it in xargs**

```bash
## List private-nics of all listed servers

# Using jq
scw -o json instance server list | jq -r '.[] | "server-id=\(.id)"' | xargs -L1 scw instance private-nic list
# Using CLI templates
scw instance server list -o template="server-id={{ .ID }}" | xargs -L1 scw instance private-nic list
```