# 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 Minify to concat and minify multiple CSS files into a single one.

version: '3'tasks:  build:    cmds:      - go build -v -i main.go  assets:    cmds:      - minify -o public/style.css src/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:

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).

## Environment variables​

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
version: '3'env:  ENV: testingdotenv: ['.env', '{{.ENV}}/.env.', '{{.HOME}}/.env']tasks:  greet:    cmds:      - echo "Using $KEYNAME and endpoint$ENDPOINT"

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.

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

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

You can also specify variables when including a Taskfile. This may be useful for having 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
##### 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"}}'.

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.

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:      - minify -o public/style.css src/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:      - minify -o public/script.js src/js  css:    cmds:      - minify -o public/style.css src/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"}    cmds:      - echo "after"  echo_sth:    cmds:      - echo {{.TEXT}}

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"

Overriding variables in the called task is as simple as informing vars attribute:

version: '3'tasks:  greet:    vars:      RECIPIENT: '{{default "World" .RECIPIENT}}'    cmds:      - echo "Hello, {{.RECIPIENT}}!"  greet-pessimistically:    cmds:      - task: greet        vars: {RECIPIENT: "Cruel World"}

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:      - minify -o public/script.js src/js    sources:      - src/js/**/*.js    generates:      - public/script.js  css:    cmds:      - minify -o public/style.css src/css    sources:      - src/css/**/*.css    generates:      - public/style.css

sources and generates can be files or file 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.

If you prefer this 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
##### 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 run the task.

##### info

For the checksum (default) method to work, it is only necessary to inform the source files, but if you want to use the timestamp method, you also need to inform the generated files with generates.

### 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.

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.

### 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"

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

## Variables​

When doing interpolation of variables, Task will look for the below. They are listed below in order of importance (i.e. 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 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}}"

### 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.

## 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}} ## 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. ## Go's template engine​ Task parse commands as Go's template engine before executing them. Variables are accessible through dot syntax (.VARNAME). All functions by the Go's slim-sprig lib are available. The following example gets the current date in a given format: version: '3'tasks: print-date: cmds: - echo {{now | date "2006-01-02"}} Task also adds the following functions: • OS: Returns the operating system. Possible values are "windows", "linux", "darwin" (macOS) and "freebsd". • ARCH: return the architecture Task was compiled to: "386", "amd64", "arm" or "s390x". • splitLines: Splits Unix (\n) and Windows (\r\n) styled newlines. • catLines: Replaces Unix (\n) and Windows (\r\n) styled newlines with a space. • toSlash: Does nothing on Unix, but on Windows converts a string from \ path format to /. • fromSlash: Opposite of toSlash. Does nothing on Unix, but on Windows converts a string from / path format to \. • exeExt: Returns the right executable extension for the current OS (".exe" for Windows, "" for others). • shellQuote: Quotes a string to make it safe for use in shell scripts. Task uses this Go function for this. The Bash dialect is assumed. Example: version: '3'tasks: print-os: cmds: - echo '{{OS}} {{ARCH}}' - echo '{{if eq OS "windows"}}windows-command{{else}}unix-command{{end}}' # This will be path/to/file on Unix but path\to\file on Windows - echo '{{fromSlash "path/to/file"}}' enumerated-file: vars: CONTENT: | foo bar cmds: - | cat << EOF > output.txt {{range$i, $line := .CONTENT | splitLines -}} {{printf "%3d"$i}}: {{$line}} {{end}}EOF ## 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: - minify -o public/script.js src/js css: cmds: - minify -o public/style.css src/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: releaseRelease your project to githubIt will build your project before starting the release.Please make sure that you have set GITHUB_TOKEN before starting.dependencies: - buildcommands: - 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. ## 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}}" ## 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: truetasks: 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::defaultHello, World!::endgroup::

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: prefixedtasks: 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.

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
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.