Skip to main content

Usage

Getting started​

Create a file called Taskfile.yml in the root of your project. The cmds attribute should contain the commands of a task. The example below allows compiling a Go app and uses esbuild to concat and minify multiple CSS files into a single one.

version: '3'

tasks:
  build:
    cmds:
      - go build -v -i main.go

  assets:
    cmds:
      - esbuild --bundle --minify css/index.css > public/bundle.css

Running the tasks is as simple as running:

task assets build

Task uses mvdan.cc/sh, a native Go sh interpreter. So you can write sh/bash commands, and it will work even on Windows, where sh or bash are usually not available. Just remember any executable called must be available by the OS or in PATH.

If you omit a task name, "default" will be assumed.

Supported file names​

Task will look for the following file names, in order of priority:

  • Taskfile.yml
  • taskfile.yml
  • Taskfile.yaml
  • taskfile.yaml
  • Taskfile.dist.yml
  • taskfile.dist.yml
  • Taskfile.dist.yaml
  • taskfile.dist.yaml

The intention of having the .dist variants is to allow projects to have one committed version (.dist) while still allowing individual users to override the Taskfile by adding an additional Taskfile.yml (which would be on .gitignore).

Running a Taskfile from a subdirectory​

If a Taskfile cannot be found in the current working directory, it will walk up the file tree until it finds one (similar to how git works). When running Task from a subdirectory like this, it will behave as if you ran it from the directory containing the Taskfile.

You can use this functionality along with the special {{.USER_WORKING_DIR}} variable to create some very useful reusable tasks. For example, if you have a monorepo with directories for each microservice, you can cd into a microservice directory and run a task command to bring it up without having to create multiple tasks or Taskfiles with identical content. For example:

version: '3'

tasks:
  up:
    dir: '{{.USER_WORKING_DIR}}'
    preconditions:
      - test -f docker-compose.yml
    cmds:
      - docker-compose up -d

In this example, we can run cd <service> and task up and as long as the <service> directory contains a docker-compose.yml, the Docker composition will be brought up.

Running a global Taskfile​

If you call Task with the --global (alias -g) flag, it will look for your home directory instead of your working directory. In short, Task will look for a Taskfile that matches $HOME/{T,t}askfile.{yml,yaml} .

This is useful to have automation that you can run from anywhere in your system!

info

When running your global Taskfile with -g, tasks will run on $HOME by default, and not on your working directory!

As mentioned in the previous section, the {{.USER_WORKING_DIR}} special variable can be very handy here to run stuff on the directory you're calling task -g from.

version: '3'

tasks:
  from-home:
    cmds:
      - pwd

  from-working-directory:
    dir: '{{.USER_WORKING_DIR}}'
    cmds:
      - pwd

Reading a Taskfile from stdin​

Taskfile also supports reading from stdin. This is useful if you are generating Taskfiles dynamically and don't want write them to disk. To tell task to read from stdin, you must specify the -t/--taskfile flag with the special - value. You may then pipe into Task as you would any other program:

task -t - <(cat ./Taskfile.yml)
# OR
cat ./Taskfile.yml | task -t -

Environment variables​

Task​

You can use env to set custom environment variables for a specific task:

version: '3'

tasks:
  greet:
    cmds:
      - echo $GREETING
    env:
      GREETING: Hey, there!

Additionally, you can set global environment variables that will be available to all tasks:

version: '3'

env:
  GREETING: Hey, there!

tasks:
  greet:
    cmds:
      - echo $GREETING
info

env supports expansion and retrieving output from a shell command just like variables, as you can see in the Variables section.

.env files​

You can also ask Task to include .env like files by using the dotenv: setting:

.env
KEYNAME=VALUE
testing/.env
ENDPOINT=testing.com
Taskfile.yml
version: '3'

env:
  ENV: testing

dotenv: ['.env', '{{.ENV}}/.env.', '{{.HOME}}/.env']

tasks:
  greet:
    cmds:
      - echo "Using $KEYNAME and endpoint $ENDPOINT"

Dotenv files can also be specified at the task level:

version: '3'

env:
  ENV: testing

tasks:
  greet:
    dotenv: ['.env', '{{.ENV}}/.env.', '{{.HOME}}/.env']
    cmds:
      - echo "Using $KEYNAME and endpoint $ENDPOINT"

Environment variables specified explicitly at the task-level will override variables defined in dotfiles:

version: '3'

env:
  ENV: testing

tasks:
  greet:
    dotenv: ['.env', '{{.ENV}}/.env.', '{{.HOME}}/.env']
    env:
      KEYNAME: DIFFERENT_VALUE
    cmds:
      - echo "Using $KEYNAME and endpoint $ENDPOINT"
info

Please note that you are not currently able to use the dotenv key inside included Taskfiles.

Including other Taskfiles​

If you want to share tasks between different projects (Taskfiles), you can use the importing mechanism to include other Taskfiles using the includes keyword:

version: '3'

includes:
  docs: ./documentation # will look for ./documentation/Taskfile.yml
  docker: ./DockerTasks.yml

The tasks described in the given Taskfiles will be available with the informed namespace. So, you'd call task docs:serve to run the serve task from documentation/Taskfile.yml or task docker:build to run the build task from the DockerTasks.yml file.

Relative paths are resolved relative to the directory containing the including Taskfile.

OS-specific Taskfiles​

With version: '2', task automatically includes any Taskfile_{{OS}}.yml if it exists (for example: Taskfile_windows.yml, Taskfile_linux.yml or Taskfile_darwin.yml). Since this behavior was a bit too implicit, it was removed on version 3, but you still can have a similar behavior by explicitly importing these files:

version: '3'

includes:
  build: ./Taskfile_{{OS}}.yml

Directory of included Taskfile​

By default, included Taskfile's tasks are run in the current directory, even if the Taskfile is in another directory, but you can force its tasks to run in another directory by using this alternative syntax:

version: '3'

includes:
  docs:
    taskfile: ./docs/Taskfile.yml
    dir: ./docs
info

The included Taskfiles must be using the same schema version as the main Taskfile uses.

Optional includes​

Includes marked as optional will allow Task to continue execution as normal if the included file is missing.

version: '3'

includes:
  tests:
    taskfile: ./tests/Taskfile.yml
    optional: true

tasks:
  greet:
    cmds:
      - echo "This command can still be successfully executed if
        ./tests/Taskfile.yml does not exist"

Internal includes​

Includes marked as internal will set all the tasks of the included file to be internal as well (see the Internal tasks section below). This is useful when including utility tasks that are not intended to be used directly by the user.

version: '3'

includes:
  tests:
    taskfile: ./taskfiles/Utils.yml
    internal: true

Flatten includes​

You can flatten the included Taskfile tasks into the main Taskfile by using the flatten option. It means that the included Taskfile tasks will be available without the namespace.

version: '3'

includes:
  lib:
    taskfile: ./Included.yml
    flatten: true

tasks:
  greet:
    cmds:
      - echo "Greet"
      - task: foo

If you run task -a it will print :

task: Available tasks for this project:
* greet:
* foo

You can run task foo directly without the namespace.

You can also reference the task in other tasks without the namespace. So if you run task greet it will run greet and foo tasks and the output will be :

If multiple tasks have the same name, an error will be thrown:

version: '3'
includes:
  lib:
	    taskfile: ./Included.yml
	    flatten: true

	tasks:
	  greet:
	    cmds:
	      - echo "Greet"
	      - task: foo

If you run task -a it will print:

task: Found multiple tasks (greet) included by "lib"

Vars of included Taskfiles​

You can also specify variables when including a Taskfile. This may be useful for having a reusable Taskfile that can be tweaked or even included more than once:

version: '3'

includes:
  backend:
    taskfile: ./taskfiles/Docker.yml
    vars:
      DOCKER_IMAGE: backend_image

  frontend:
    taskfile: ./taskfiles/Docker.yml
    vars:
      DOCKER_IMAGE: frontend_image

Namespace aliases​

When including a Taskfile, you can give the namespace a list of aliases. This works in the same way as task aliases and can be used together to create shorter and easier-to-type commands.

version: '3'

includes:
  generate:
    taskfile: ./taskfiles/Generate.yml
    aliases: [gen]
info

Vars declared in the included Taskfile have preference over the variables in the including Taskfile! If you want a variable in an included Taskfile to be overridable, use the default function: MY_VAR: '{{.MY_VAR | default "my-default-value"}}'.

Internal tasks​

Internal tasks are tasks that cannot be called directly by the user. They will not appear in the output when running task --list|--list-all. Other tasks may call internal tasks in the usual way. This is useful for creating reusable, function-like tasks that have no useful purpose on the command line.

version: '3'

tasks:
  build-image-1:
    cmds:
      - task: build-image
        vars:
          DOCKER_IMAGE: image-1

  build-image:
    internal: true
    cmds:
      - docker build -t {{.DOCKER_IMAGE}} .

Task directory​

By default, tasks will be executed in the directory where the Taskfile is located. But you can easily make the task run in another folder, informing dir:

version: '3'

tasks:
  serve:
    dir: public/www
    cmds:
      # run http server
      - caddy

If the directory does not exist, task creates it.

Task dependencies​

Dependencies run in parallel, so dependencies of a task should not depend one another. If you want to force tasks to run serially, take a look at the Calling Another Task section below.

You may have tasks that depend on others. Just pointing them on deps will make them run automatically before running the parent task:

version: '3'

tasks:
  build:
    deps: [assets]
    cmds:
      - go build -v -i main.go

  assets:
    cmds:
      - esbuild --bundle --minify css/index.css > public/bundle.css

In the above example, assets will always run right before build if you run task build.

A task can have only dependencies and no commands to group tasks together:

version: '3'

tasks:
  assets:
    deps: [js, css]

  js:
    cmds:
      - esbuild --bundle --minify js/index.js > public/bundle.js

  css:
    cmds:
      - esbuild --bundle --minify css/index.css > public/bundle.css

If there is more than one dependency, they always run in parallel for better performance.

tip

You can also make the tasks given by the command line run in parallel by using the --parallel flag (alias -p). Example: task --parallel js css.

If you want to pass information to dependencies, you can do that the same manner as you would to call another task:

version: '3'

tasks:
  default:
    deps:
      - task: echo_sth
        vars: { TEXT: 'before 1' }
      - task: echo_sth
        vars: { TEXT: 'before 2' }
        silent: true
    cmds:
      - echo "after"

  echo_sth:
    cmds:
      - echo {{.TEXT}}

Platform specific tasks and commands​

If you want to restrict the running of tasks to explicit platforms, this can be achieved using the platforms: key. Tasks can be restricted to a specific OS, architecture or a combination of both. On a mismatch, the task or command will be skipped, and no error will be thrown.

The values allowed as OS or Arch are valid GOOS and GOARCH values, as defined by the Go language here.

The build-windows task below will run only on Windows, and on any architecture:

version: '3'

tasks:
  build-windows:
    platforms: [windows]
    cmds:
      - echo 'Running command on Windows'

This can be restricted to a specific architecture as follows:

version: '3'

tasks:
  build-windows-amd64:
    platforms: [windows/amd64]
    cmds:
      - echo 'Running command on Windows (amd64)'

It is also possible to restrict the task to specific architectures:

version: '3'

tasks:
  build-amd64:
    platforms: [amd64]
    cmds:
      - echo 'Running command on amd64'

Multiple platforms can be specified as follows:

version: '3'

tasks:
  build:
    platforms: [windows/amd64, darwin]
    cmds:
      - echo 'Running command on Windows (amd64) and macOS'

Individual commands can also be restricted to specific platforms:

version: '3'

tasks:
  build:
    cmds:
      - cmd: echo 'Running command on Windows (amd64) and macOS'
        platforms: [windows/amd64, darwin]
      - cmd: echo 'Running on all platforms'

Calling another task​

When a task has many dependencies, they are executed concurrently. This will often result in a faster build pipeline. However, in some situations, you may need to call other tasks serially. In this case, use the following syntax:

version: '3'

tasks:
  main-task:
    cmds:
      - task: task-to-be-called
      - task: another-task
      - echo "Both done"

  task-to-be-called:
    cmds:
      - echo "Task to be called"

  another-task:
    cmds:
      - echo "Another task"

Using the vars and silent attributes you can choose to pass variables and toggle silent mode on a call-by-call basis:

version: '3'

tasks:
  greet:
    vars:
      RECIPIENT: '{{default "World" .RECIPIENT}}'
    cmds:
      - echo "Hello, {{.RECIPIENT}}!"

  greet-pessimistically:
    cmds:
      - task: greet
        vars: { RECIPIENT: 'Cruel World' }
        silent: true

The above syntax is also supported in deps.

tip

NOTE: If you want to call a task declared in the root Taskfile from within an included Taskfile, add a leading : like this: task: :task-name.

Prevent unnecessary work​

By fingerprinting locally generated files and their sources​

If a task generates something, you can inform Task the source and generated files, so Task will prevent running them if not necessary.

version: '3'

tasks:
  build:
    deps: [js, css]
    cmds:
      - go build -v -i main.go

  js:
    cmds:
      - esbuild --bundle --minify js/index.js > public/bundle.js
    sources:
      - src/js/**/*.js
    generates:
      - public/bundle.js

  css:
    cmds:
      - esbuild --bundle --minify css/index.css > public/bundle.css
    sources:
      - src/css/**/*.css
    generates:
      - public/bundle.css

sources and generates can be files or glob patterns. When given, Task will compare the checksum of the source files to determine if it's necessary to run the task. If not, it will just print a message like Task "js" is up to date.

exclude: can also be used to exclude files from fingerprinting. Sources are evaluated in order, so exclude: must come after the positive glob it is negating.

version: '3'

tasks:
  css:
    sources:
      - mysources/**/*.css
      - exclude: mysources/ignoreme.css
    generates:
      - public/bundle.css

If you prefer these check to be made by the modification timestamp of the files, instead of its checksum (content), just set the method property to timestamp.

version: '3'

tasks:
  build:
    cmds:
      - go build .
    sources:
      - ./*.go
    generates:
      - app{{exeExt}}
    method: timestamp

In situations where you need more flexibility the status keyword can be used. You can even combine the two. See the documentation for status for an example.

info

By default, task stores checksums on a local .task directory in the project's directory. Most of the time, you'll want to have this directory on .gitignore (or equivalent) so it isn't committed. (If you have a task for code generation that is committed it may make sense to commit the checksum of that task as well, though).

If you want these files to be stored in another directory, you can set a TASK_TEMP_DIR environment variable in your machine. It can contain a relative path like tmp/task that will be interpreted as relative to the project directory, or an absolute or home path like /tmp/.task or ~/.task (subdirectories will be created for each project).

export TASK_TEMP_DIR='~/.task'
info

Each task has only one checksum stored for its sources. If you want to distinguish a task by any of its input variables, you can add those variables as part of the task's label, and it will be considered a different task.

This is useful if you want to run a task once for each distinct set of inputs until the sources actually change. For example, if the sources depend on the value of a variable, or you if you want the task to rerun if some arguments change even if the source has not.

tip

The method none skips any validation and always runs the task.

info

For the checksum (default) or timestamp method to work, it is only necessary to inform the source files. When the timestamp method is used, the last time of the running the task is considered as a generate.

Using programmatic checks to indicate a task is up to date​

Alternatively, you can inform a sequence of tests as status. If no error is returned (exit status 0), the task is considered up-to-date:

version: '3'

tasks:
  generate-files:
    cmds:
      - mkdir directory
      - touch directory/file1.txt
      - touch directory/file2.txt
    # test existence of files
    status:
      - test -d directory
      - test -f directory/file1.txt
      - test -f directory/file2.txt

Normally, you would use sources in combination with generates - but for tasks that generate remote artifacts (Docker images, deploys, CD releases) the checksum source and timestamps require either access to the artifact or for an out-of-band refresh of the .checksum fingerprint file.

Two special variables {{.CHECKSUM}} and {{.TIMESTAMP}} are available for interpolation within status commands, depending on the method assigned to fingerprint the sources. Only source globs are fingerprinted.

Note that the {{.TIMESTAMP}} variable is a "live" Go time.Time struct, and can be formatted using any of the methods that time.Time responds to.

See the Go Time documentation for more information.

You can use --force or -f if you want to force a task to run even when up-to-date.

Also, task --status [tasks]... will exit with a non-zero exit code if any of the tasks are not up-to-date.

status can be combined with the fingerprinting to have a task run if either the the source/generated artifacts changes, or the programmatic check fails:

version: '3'

tasks:
  build:prod:
    desc: Build for production usage.
    cmds:
      - composer install
    # Run this task if source files changes.
    sources:
      - composer.json
      - composer.lock
    generates:
      - ./vendor/composer/installed.json
      - ./vendor/autoload.php
    # But also run the task if the last build was not a production build.
    status:
      - grep -q '"dev": false' ./vendor/composer/installed.json

Using programmatic checks to cancel the execution of a task and its dependencies​

In addition to status checks, preconditions checks are the logical inverse of status checks. That is, if you need a certain set of conditions to be true you can use the preconditions stanza. preconditions are similar to status lines, except they support sh expansion, and they SHOULD all return 0.

version: '3'

tasks:
  generate-files:
    cmds:
      - mkdir directory
      - touch directory/file1.txt
      - touch directory/file2.txt
    # test existence of files
    preconditions:
      - test -f .env
      - sh: '[ 1 = 0 ]'
        msg: "One doesn't equal Zero, Halting"

Preconditions can set specific failure messages that can tell a user what steps to take using the msg field.

If a task has a dependency on a sub-task with a precondition, and that precondition is not met - the calling task will fail. Note that a task executed with a failing precondition will not run unless --force is given.

Unlike status, which will skip a task if it is up to date and continue executing tasks that depend on it, a precondition will fail a task, along with any other tasks that depend on it.

version: '3'

tasks:
  task-will-fail:
    preconditions:
      - sh: 'exit 1'

  task-will-also-fail:
    deps:
      - task-will-fail

  task-will-still-fail:
    cmds:
      - task: task-will-fail
      - echo "I will not run"

Limiting when tasks run​

If a task executed by multiple cmds or multiple deps you can control when it is executed using run. run can also be set at the root of the Taskfile to change the behavior of all the tasks unless explicitly overridden.

Supported values for run:

  • always (default) always attempt to invoke the task regardless of the number of previous executions
  • once only invoke this task once regardless of the number of references
  • when_changed only invokes the task once for each unique set of variables passed into the task
version: '3'

tasks:
  default:
    cmds:
      - task: generate-file
        vars: { CONTENT: '1' }
      - task: generate-file
        vars: { CONTENT: '2' }
      - task: generate-file
        vars: { CONTENT: '2' }

  generate-file:
    run: when_changed
    deps:
      - install-deps
    cmds:
      - echo {{.CONTENT}}

  install-deps:
    run: once
    cmds:
      - sleep 5 # long operation like installing packages

Ensuring required variables are set​

If you want to check that certain variables are set before running a task then you can use requires. This is useful when might not be clear to users which variables are needed, or if you want clear message about what is required. Also some tasks could have dangerous side effects if run with un-set variables.

Using requires you specify an array of strings in the vars sub-section under requires, these strings are variable names which are checked prior to running the task. If any variables are un-set the the task will error and not run.

Environmental variables are also checked.

Syntax:

requires:
  vars: [] # Array of strings
note

Variables set to empty zero length strings, will pass the requires check.

Example of using requires:

version: '3'

tasks:
  docker-build:
    cmds:
      - 'docker build . -t {{.IMAGE_NAME}}:{{.IMAGE_TAG}}'

    # Make sure these variables are set before running
    requires:
      vars: [IMAGE_NAME, IMAGE_TAG]

Ensuring required variables have allowed values​

If you want to ensure that a variable is set to one of a predefined set of valid values before executing a task, you can use requires. This is particularly useful when there are strict requirements for what values a variable can take, and you want to provide clear feedback to the user when an invalid value is detected.

To use requires, you specify an array of allowed values in the vars sub-section under requires. Task will check if the variable is set to one of the allowed values. If the variable does not match any of these values, the task will raise an error and stop execution.

This check applies both to user-defined variables and environment variables.

Example of using requires:

version: '3'

tasks:
  deploy:
    cmds:
      - echo "deploying to {{.ENV}}"

    requires:
      vars:
        - name: ENV
          enum: [dev, beta, prod]

If ENV is not one of 'dev', 'beta' or 'prod' an error will be raised.

note

This is supported only for string variables.

Variables​

Task allows you to set variables using the vars keyword. The following variable types are supported:

  • string
  • bool
  • int
  • float
  • array
note

Maps are not supported by default, but there is an experiment that can be enabled to add support. If you're interested in this functionality, we would appreciate your feedback. 🙏

In the meantime, it is technically possible to define a map using a ref resolver and a templating function. For example:

version: '3'

tasks:
  task-with-map:
    vars:
      FOO:
        ref: dict "a" "1" "b" "2" "c" "3"
    cmds:
      - echo {{.FOO}}
map[a:1 b:2 c:3]

OR by using the same technique with JSON:

version: '3'

tasks:
  task-with-map:
    vars:
      JSON: '{"a": 1, "b": 2, "c": 3}'
      FOO:
        ref: "fromJson .JSON"
    cmds:
      - echo {{.FOO}}
map[a:1 b:2 c:3]

Variables can be set in many places in a Taskfile. When executing templates, Task will look for variables in the order listed below (most important first):

  • Variables declared in the task definition
  • Variables given while calling a task from another (See Calling another task above)
  • Variables of the included Taskfile (when the task is included)
  • Variables of the inclusion of the Taskfile (when the task is included)
  • Global variables (those declared in the vars: option in the Taskfile)
  • Environment variables

Example of sending parameters with environment variables:

$ TASK_VARIABLE=a-value task do-something
tip

A special variable .TASK is always available containing the task name.

Since some shells do not support the above syntax to set environment variables (Windows) tasks also accept a similar style when not at the beginning of the command.

$ task write-file FILE=file.txt "CONTENT=Hello, World!" print "MESSAGE=All done!"

Example of locally declared vars:

version: '3'

tasks:
  print-var:
    cmds:
      - echo "{{.VAR}}"
    vars:
      VAR: Hello!

Example of global vars in a Taskfile.yml:

version: '3'

vars:
  GREETING: Hello from Taskfile!

tasks:
  greet:
    cmds:
      - echo "{{.GREETING}}"

Example of a default value to be overridden from CLI:

version: '3'

  greet_user:
    desc: "Greet the user with a name."
    vars:
      USER_NAME: '{{.USER_NAME| default "DefaultUser"}}'
    cmds:
      - echo "Hello, {{.USER_NAME}}!"
$ task greet_user
task: [greet_user] echo "Hello, DefaultUser!"
Hello, DefaultUser!
$ task greet_user USER_NAME="Bob"
task: [greet_user] echo "Hello, Bob!"
Hello, Bob!

Dynamic variables​

The below syntax (sh: prop in a variable) is considered a dynamic variable. The value will be treated as a command and the output assigned. If there are one or more trailing newlines, the last newline will be trimmed.

version: '3'

tasks:
  build:
    cmds:
      - go build -ldflags="-X main.Version={{.GIT_COMMIT}}" main.go
    vars:
      GIT_COMMIT:
        sh: git log -n 1 --format=%h

This works for all types of variables.

Referencing other variables​

Templating is great for referencing string values if you want to pass a value from one task to another. However, the templating engine is only able to output strings. If you want to pass something other than a string to another task then you will need to use a reference (ref) instead.

version: 3

tasks:
  foo:
    vars:
      FOO: [A, B, C] # <-- FOO is defined as an array
    cmds:
      - task: bar
        vars:
          FOO:
            ref: .FOO # <-- FOO gets passed by reference to bar and maintains its type
  bar:
    cmds:
      - 'echo {{index .FOO 0}}' # <-- FOO is still a map so the task outputs 'A' as expected

This also works the same way when calling deps and when defining a variable and can be used in any combination:

version: 3

tasks:
  foo:
    vars:
      FOO: [A, B, C] # <-- FOO is defined as an array
      BAR:
        ref: .FOO # <-- BAR is defined as a reference to FOO
    deps:
      - task: bar
        vars:
          BAR:
            ref: .BAR # <-- BAR gets passed by reference to bar and maintains its type
  bar:
    cmds:
      - 'echo {{index .BAR 0}}' # <-- BAR still refers to FOO so the task outputs 'A'

All references use the same templating syntax as regular templates, so in addition to simply calling .FOO, you can also pass subkeys (.FOO.BAR) or indexes (index .FOO 0) and use functions (len .FOO) as described in the templating-reference:

version: 3

tasks:
  foo:
    vars:
      FOO: [A, B, C] # <-- FOO is defined as an array
    cmds:
      - task: bar
        vars:
          FOO:
            ref: index .FOO 0 # <-- The element at index 0 is passed by reference to bar
  bar:
    cmds:
      - 'echo {{.FOO}}' # <-- FOO is just the letter 'A'

Looping over values​

Task allows you to loop over certain values and execute a command for each. There are a number of ways to do this depending on the type of value you want to loop over.

Looping over a static list​

The simplest kind of loop is an explicit one. This is useful when you want to loop over a set of values that are known ahead of time.

version: '3'

tasks:
  default:
    cmds:
      - for: ['foo.txt', 'bar.txt']
        cmd: cat {{ .ITEM }}

Looping over a matrix​

If you need to loop over all permutations of multiple lists, you can use the matrix property. This should be familiar to anyone who has used a matrix in a CI/CD pipeline.

version: '3'

tasks:
  default:
    silent: true
    cmds:
      - for:
          matrix:
            OS: ["windows", "linux", "darwin"]
            ARCH: ["amd64", "arm64"]
        cmd: echo "{{.ITEM.OS}}/{{.ITEM.ARCH}}"

This will output:

windows/amd64
windows/arm64
linux/amd64
linux/arm64
darwin/amd64
darwin/arm64

Looping over your task's sources​

You are also able to loop over the sources of your task:

version: '3'

tasks:
  default:
    sources:
      - foo.txt
      - bar.txt
    cmds:
      - for: sources
        cmd: cat {{ .ITEM }}

This will also work if you use globbing syntax in your sources. For example, if you specify a source for *.txt, the loop will iterate over all files that match that glob.

Source paths will always be returned as paths relative to the task directory. If you need to convert this to an absolute path, you can use the built-in joinPath function. There are some special variables that you may find useful for this.

version: '3'

tasks:
  default:
    vars:
      MY_DIR: /path/to/dir
    dir: '{{.MY_DIR}}'
    sources:
      - foo.txt
      - bar.txt
    cmds:
      - for: sources
        cmd: cat {{joinPath .MY_DIR .ITEM}}

Looping over variables​

To loop over the contents of a variable, you simply need to specify the variable you want to loop over. By default, string variables will be split on any whitespace characters.

version: '3'

tasks:
  default:
    vars:
      MY_VAR: foo.txt bar.txt
    cmds:
      - for: { var: MY_VAR }
        cmd: cat {{.ITEM}}

If you need to split a string on a different character, you can do this by specifying the split property:

version: '3'

tasks:
  default:
    vars:
      MY_VAR: foo.txt,bar.txt
    cmds:
      - for: { var: MY_VAR, split: ',' }
        cmd: cat {{.ITEM}}

You can also loop over arrays directly and maps:

version: 3

tasks:
  foo:
    vars:
      LIST: [foo, bar, baz]
    cmds:
      - for:
          var: LIST
        cmd: echo {{.ITEM}}

When looping over a map we also make an additional {{.KEY}} variable available that holds the string value of the map key. Remember that maps are unordered, so the order in which the items are looped over is random.

All of this also works with dynamic variables!

version: '3'

tasks:
  default:
    vars:
      MY_VAR:
        sh: find -type f -name '*.txt'
    cmds:
      - for: { var: MY_VAR }
        cmd: cat {{.ITEM}}

Renaming variables​

If you want to rename the iterator variable to make it clearer what the value contains, you can do so by specifying the as property:

version: '3'

tasks:
  default:
    vars:
      MY_VAR: foo.txt bar.txt
    cmds:
      - for: { var: MY_VAR, as: FILE }
        cmd: cat {{.FILE}}

Looping over tasks​

Because the for property is defined at the cmds level, you can also use it alongside the task keyword to run tasks multiple times with different variables.

version: '3'

tasks:
  default:
    cmds:
      - for: [foo, bar]
        task: my-task
        vars:
          FILE: '{{.ITEM}}'

  my-task:
    cmds:
      - echo '{{.FILE}}'

Or if you want to run different tasks depending on the value of the loop:

version: '3'

tasks:
  default:
    cmds:
      - for: [foo, bar]
        task: task-{{.ITEM}}

  task-foo:
    cmds:
      - echo 'foo'

  task-bar:
    cmds:
      - echo 'bar'

Looping over dependencies​

All of the above looping techniques can also be applied to the deps property. This allows you to combine loops with concurrency:

version: '3'

tasks:
  default:
    deps:
      - for: [foo, bar]
        task: my-task
        vars:
          FILE: '{{.ITEM}}'

  my-task:
    cmds:
      - echo '{{.FILE}}'

It is important to note that as deps are run in parallel, the order in which the iterations are run is not guaranteed and the output may vary. For example, the output of the above example may be either:

foo
bar

or

bar
foo

Forwarding CLI arguments to commands​

If -- is given in the CLI, all following parameters are added to a special .CLI_ARGS variable. This is useful to forward arguments to another command.

The below example will run yarn install.

$ task yarn -- install
version: '3'

tasks:
  yarn:
    cmds:
      - yarn {{.CLI_ARGS}}

Wildcard arguments​

Another way to parse arguments into a task is to use a wildcard in your task's name. Wildcards are denoted by an asterisk (*) and can be used multiple times in a task's name to pass in multiple arguments.

Matching arguments will be captured and stored in the .MATCH variable and can then be used in your task's commands like any other variable. This variable is an array of strings and so will need to be indexed to access the individual arguments. We suggest creating a named variable for each argument to make it clear what they contain:

version: '3'

tasks:
  echo-*:
    vars:
      TEXT: '{{index .MATCH 0}}'
    cmds:
      - echo {{.TEXT}}

  run-*-*:
    vars:
      ARG_1: '{{index .MATCH 0}}'
      ARG_2: '{{index .MATCH 1}}'
    cmds:
      - echo {{.ARG_1}} {{.ARG_2}}
# This call matches the "echo-*" task and the string "hello" is captured by the
# wildcard and stored in the .MATCH variable. We then index the .MATCH array and
# store the result in the .TEXT variable which is then echoed out in the cmds.
$ task echo-hello
hello
# You can use whitespace in your arguments as long as you quote the task name
$ task "echo-hello world"
hello world
# And you can pass multiple arguments
$ task run-foo-bar
foo bar

If multiple matching tasks are found, an error occurs. If you are using included Taskfiles, tasks in parent files will be considered first.

Doing task cleanup with defer​

With the defer keyword, it's possible to schedule cleanup to be run once the task finishes. The difference with just putting it as the last command is that this command will run even when the task fails.

In the example below, rm -rf tmpdir/ will run even if the third command fails:

version: '3'

tasks:
  default:
    cmds:
      - mkdir -p tmpdir/
      - defer: rm -rf tmpdir/
      - echo 'Do work on tmpdir/'

If you want to move the cleanup command into another task, that is possible as well:

version: '3'

tasks:
  default:
    cmds:
      - mkdir -p tmpdir/
      - defer: { task: cleanup }
      - echo 'Do work on tmpdir/'

  cleanup: rm -rf tmpdir/
info

Due to the nature of how the Go's own defer work, the deferred commands are executed in the reverse order if you schedule multiple of them.

A special variable .EXIT_CODE is exposed when a command exited with a non-zero exit code. You can check its presence to know if the task completed successfully or not:

version: '3'

tasks:
  default:
    cmds:
      - defer: echo '{{if .EXIT_CODE}}Failed with {{.EXIT_CODE}}!{{else}}Success!{{end}}'
      - exit 1

Help​

Running task --list (or task -l) lists all tasks with a description. The following Taskfile:

version: '3'

tasks:
  build:
    desc: Build the go binary.
    cmds:
      - go build -v -i main.go

  test:
    desc: Run all the go tests.
    cmds:
      - go test -race ./...

  js:
    cmds:
      - esbuild --bundle --minify js/index.js > public/bundle.js

  css:
    cmds:
      - esbuild --bundle --minify css/index.css > public/bundle.css

would print the following output:

* build:   Build the go binary.
* test:    Run all the go tests.

If you want to see all tasks, there's a --list-all (alias -a) flag as well.

Display summary of task​

Running task --summary task-name will show a summary of a task. The following Taskfile:

version: '3'

tasks:
  release:
    deps: [build]
    summary: |
      Release your project to github

      It will build your project before starting the release.
      Please make sure that you have set GITHUB_TOKEN before starting.
    cmds:
      - your-release-tool

  build:
    cmds:
      - your-build-tool

with running task --summary release would print the following output:

task: release

Release your project to github

It will build your project before starting the release.
Please make sure that you have set GITHUB_TOKEN before starting.

dependencies:
 - build

commands:
 - your-release-tool

If a summary is missing, the description will be printed. If the task does not have a summary or a description, a warning is printed.

Please note: showing the summary will not execute the command.

Task aliases​

Aliases are alternative names for tasks. They can be used to make it easier and quicker to run tasks with long or hard-to-type names. You can use them on the command line, when calling sub-tasks in your Taskfile and when including tasks with aliases from another Taskfile. They can also be used together with namespace aliases.

version: '3'

tasks:
  generate:
    aliases: [gen]
    cmds:
      - task: gen-mocks

  generate-mocks:
    aliases: [gen-mocks]
    cmds:
      - echo "generating..."

Overriding task name​

Sometimes you may want to override the task name printed on the summary, up-to-date messages to STDOUT, etc. In this case, you can just set label:, which can also be interpolated with variables:

version: '3'

tasks:
  default:
    - task: print
      vars:
        MESSAGE: hello
    - task: print
      vars:
        MESSAGE: world

  print:
    label: 'print-{{.MESSAGE}}'
    cmds:
      - echo "{{.MESSAGE}}"

Warning Prompts​

Warning Prompts are used to prompt a user for confirmation before a task is executed.

Below is an example using prompt with a dangerous command, that is called between two safe commands:

version: '3'

tasks:
  example:
    cmds:
      - task: not-dangerous
      - task: dangerous
      - task: another-not-dangerous

  not-dangerous:
    cmds:
      - echo 'not dangerous command'

  another-not-dangerous:
    cmds:
      - echo 'another not dangerous command'

  dangerous:
    prompt: This is a dangerous command... Do you want to continue?
    cmds:
      - echo 'dangerous command'
❯ task dangerous
task: "This is a dangerous command... Do you want to continue?" [y/N]

Prompts can be a single value or a list of prompts, like below:

version: '3'

tasks:
  example:
    cmds:
      - task: dangerous

  dangerous:
    prompt:
     - This is a dangerous command... Do you want to continue?
     - Are you sure?
    cmds:
      - echo 'dangerous command'

Warning prompts are called before executing a task. If a prompt is denied Task will exit with exit code 205. If approved, Task will continue as normal.

❯ task example
not dangerous command
task: "This is a dangerous command. Do you want to continue?" [y/N]
y
dangerous command
another not dangerous command

To skip warning prompts automatically, you can use the --yes (alias -y) option when calling the task. By including this option, all warnings, will be automatically confirmed, and no prompts will be shown.

caution

Tasks with prompts always fail by default on non-terminal environments, like a CI, where an stdin won't be available for the user to answer. In those cases, use --yes (-y) to force all tasks with a prompt to run.

Silent mode​

Silent mode disables the echoing of commands before Task runs it. For the following Taskfile:

version: '3'

tasks:
  echo:
    cmds:
      - echo "Print something"

Normally this will be printed:

echo "Print something"
Print something

With silent mode on, the below will be printed instead:

Print something

There are four ways to enable silent mode:

  • At command level:
version: '3'

tasks:
  echo:
    cmds:
      - cmd: echo "Print something"
        silent: true
  • At task level:
version: '3'

tasks:
  echo:
    cmds:
      - echo "Print something"
    silent: true
  • Globally at Taskfile level:
version: '3'

silent: true

tasks:
  echo:
    cmds:
      - echo "Print something"
  • Or globally with --silent or -s flag

If you want to suppress STDOUT instead, just redirect a command to /dev/null:

version: '3'

tasks:
  echo:
    cmds:
      - echo "This will print nothing" > /dev/null

Dry run mode​

Dry run mode (--dry) compiles and steps through each task, printing the commands that would be run without executing them. This is useful for debugging your Taskfiles.

Ignore errors​

You have the option to ignore errors during command execution. Given the following Taskfile:

version: '3'

tasks:
  echo:
    cmds:
      - exit 1
      - echo "Hello World"

Task will abort the execution after running exit 1 because the status code 1 stands for EXIT_FAILURE. However, it is possible to continue with execution using ignore_error:

version: '3'

tasks:
  echo:
    cmds:
      - cmd: exit 1
        ignore_error: true
      - echo "Hello World"

ignore_error can also be set for a task, which means errors will be suppressed for all commands. Nevertheless, keep in mind that this option will not propagate to other tasks called either by deps or cmds!

Output syntax​

By default, Task just redirects the STDOUT and STDERR of the running commands to the shell in real-time. This is good for having live feedback for logging printed by commands, but the output can become messy if you have multiple commands running simultaneously and printing lots of stuff.

To make this more customizable, there are currently three different output options you can choose:

  • interleaved (default)
  • group
  • prefixed

To choose another one, just set it to root in the Taskfile:

version: '3'

output: 'group'

tasks:
  # ...

The group output will print the entire output of a command once after it finishes, so you will not have live feedback for commands that take a long time to run.

When using the group output, you can optionally provide a templated message to print at the start and end of the group. This can be useful for instructing CI systems to group all of the output for a given task, such as with GitHub Actions' ::group:: command or Azure Pipelines.

version: '3'

output:
  group:
    begin: '::group::{{.TASK}}'
    end: '::endgroup::'

tasks:
  default:
    cmds:
      - echo 'Hello, World!'
    silent: true
$ task default
::group::default
Hello, World!
::endgroup::

When using the group output, you may swallow the output of the executed command on standard output and standard error if it does not fail (zero exit code).

version: '3'

silent: true

output:
  group:
    error_only: true

tasks:
  passes: echo 'output-of-passes'
  errors: echo 'output-of-errors' && exit 1
$ task passes
$ task errors
output-of-errors
task: Failed to run task "errors": exit status 1

The prefix output will prefix every line printed by a command with [task-name] as the prefix, but you can customize the prefix for a command with the prefix: attribute:

version: '3'

output: prefixed

tasks:
  default:
    deps:
      - task: print
        vars: { TEXT: foo }
      - task: print
        vars: { TEXT: bar }
      - task: print
        vars: { TEXT: baz }

  print:
    cmds:
      - echo "{{.TEXT}}"
    prefix: 'print-{{.TEXT}}'
    silent: true
$ task default
[print-foo] foo
[print-bar] bar
[print-baz] baz
tip

The output option can also be specified by the --output or -o flags.

Interactive CLI application​

When running interactive CLI applications inside Task they can sometimes behave weirdly, especially when the output mode is set to something other than interleaved (the default), or when interactive apps are run in parallel with other tasks.

The interactive: true tells Task this is an interactive application and Task will try to optimize for it:

version: '3'

tasks:
  default:
    cmds:
      - vim my-file.txt
    interactive: true

If you still have problems running an interactive app through Task, please open an issue about it.

Short task syntax​

Starting on Task v3, you can now write tasks with a shorter syntax if they have the default settings (e.g. no custom env:, vars:, desc:, silent: , etc):

version: '3'

tasks:
  build: go build -v -o ./app{{exeExt}} .

  run:
    - task: build
    - ./app{{exeExt}} -h localhost -p 8080

set and shopt​

It's possible to specify options to the set and shopt builtins. This can be added at global, task or command level.

version: '3'

set: [pipefail]
shopt: [globstar]

tasks:
  # `globstar` required for double star globs to work
  default: echo **/*.go
info

Keep in mind that not all options are available in the shell interpreter library that Task uses.

Watch tasks​

With the flags --watch or -w task will watch for file changes and run the task again. This requires the sources attribute to be given, so task knows which files to watch.

The default watch interval is 5 seconds, but it's possible to change it by either setting interval: '500ms' in the root of the Taskfile or by passing it as an argument like --interval=500ms.

Also, it's possible to set watch: true in a given task and it'll automatically run in watch mode:

version: '3'

interval: 500ms

tasks:
  build:
    desc: Builds the Go application
    watch: true
    sources:
      - '**/*.go'
    cmds:
      - go build # ...
info

Note that when setting watch: true to a task, it'll only run in watch mode when running from the CLI via task my-watch-task, but won't run in watch mode if called by another task, either directly or as a dependency.