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Running commands

It can be very cumbersome to launch simple shell commands across the workspace since it often requires to change the current directory.

Blaze provides a simple way to launch commands from the root folder of any project, using the spawn subcommand.

The spawn command re-uses some concepts from the run command, such as project selection and parallelism, but please note that unlike Blaze targets system, it does not benefit from any cache feature. We strongly recommend to write targets as soon as possible when executing commands in your development cycle, and not rely too much on the spawn command.

Basic usage​

This command will list the files at the root of a project called my-project.

blaze spawn -p my-project ls

In fact, the spawn subcommand accepts the same selection options as the run command.

If you have options starting with dashes in the command argument, you need to prefix it with --:

blaze spawn -p my-project -- ls -lah

Note that you might have to escape some parts of the command since it might contain some special characters that will get interpreted in your current shell:

blaze spawn -p my-project --

The spawn command argument will always be executed in a shell. All environment variables will be loaded from .env files, just like the run command.

Multiple projects​

This command will list the files at the root of project-1, project-2 and project-3.

blaze spawn -p project-1,project-2,project-3 -- ls

You can also use the -a/--all flag in order to launch the command in every project.

The --include/--exclude patterns are also supported.

Default project selection​

Just like the run command, the workspace default project selector will be used if no selection option is provided.

blaze spawn ls

Checkout this section for more information about how to configure the default project selector.

Customizing the shell​

If you want to customize the shell program that is used to launch the command, you can pass an -s (or --shell) option :

blaze spawn -s /bin/zsh -p my-project -- ls

When needed, you can specify the shell kind (similarly to the std:commands executor), using the --shell-type option :

blaze spawn -s /bin/some-weird-shell --shell-type Posix -p my-project -- ls

Parallelism​

One of the advantages of using the spawn command is that you can run commands in parallel across multiple projects.

It is configured very much like the run subcommand.

The default degree of parallelism is None, which means commands will run sequentially.

The setting defined at the workspace level (settings.parallelism) can globally override the default value.

You can also use the --parallelism/-p option

Templating​

You can interpolate strings within the command provided to spawn.

In this example, all project names are displayed :

blaze spawn --all -- echo {{ project.name }}

Available variables are :