Concurrently

  master branch status


Run multiple commands concurrently.
Like npm run watch-js & npm run watch-less but better.


Table of contents
- Concurrently
- Why
- Install
- Usage
- Programmatic Usage
- [concurrently(commands[, options])](#concurrentlycommands-options)
- FAQ

Why

I like task automation with npm
but the usual way to run multiple commands concurrently is
npm run watch-js & npm run watch-css. That's fine but it's hard to keep
on track of different outputs. Also if one process fails, others still keep running
and you won't even notice the difference.

Another option would be to just run all commands in separate terminals. I got
tired of opening terminals and made concurrently.

Features:

* Cross platform (including Windows)
* Output is easy to follow with prefixes
* With --kill-others switch, all commands are killed if one dies
* Spawns commands with spawn-command

Install

The tool is written in Node.js, but you can use it to run any commands.

``bash
npm install -g concurrently
`

or if you are using it from npm scripts:

`bash
npm install concurrently --save
`

Usage

Remember to surround separate commands with quotes:
`bash
concurrently "command1 arg" "command2 arg"
`

Otherwise concurrently would try to run 4 separate commands:
command1, arg, command2, arg.

In package.json, escape quotes:

`bash
"start": "concurrently \"command1 arg\" \"command2 arg\""
`

NPM run commands can be shortened:

`bash
concurrently "npm:watch-js" "npm:watch-css" "npm:watch-node"

Equivalent to:


concurrently -n watch-js,watch-css,watch-node "npm run watch-js" "npm run watch-css" "npm run watch-node"
`

NPM shortened commands also support wildcards. Given the following scripts in
package.json:

`javascript
{
//...
"scripts": {
// ...
"watch-js": "...",
"watch-css": "...",
"watch-node": "...",
// ...
},
// ...
}
`

`bash
concurrently "npm:watch-*"

Equivalent to:

concurrently -n js,css,node "npm run watch-js" "npm run watch-css" "npm run watch-node"

Any name provided for the wildcard command will be used as a prefix to the wildcard

part of the script name:

concurrently -n w: npm:watch-*

Equivalent to:

concurrently -n w:js,w:css,w:node "npm run watch-js" "npm run watch-css" "npm run watch-node"
`

Good frontend one-liner example here.

Help:

`

concurrently [options]

General
-m, --max-processes How many processes should run at once.
New processes only spawn after all restart tries of a
process. [number]
-n, --names List of custom names to be used in prefix template.
Example names: "main,browser,server" [string]
--name-separator The character to split on. Example usage:
concurrently -n "styles|scripts|server" --name-separator
"|" [default: ","]
-r, --raw Output only raw output of processes, disables prettifying
and concurrently coloring. [boolean]
-s, --success Return exit code of zero or one based on the success or
failure of the "first" child to terminate, the "last
child", or succeed only if "all" child processes succeed.
[choices: "first", "last", "all"] [default: "all"]
--no-color Disables colors from logging [boolean]

Prefix styling
-p, --prefix Prefix used in logging for each process.
Possible values: index, pid, time, command, name,
none, or a template. Example template: "{time}-{pid}"
[string] [default: index or name (when --names is set)]
-c, --prefix-colors Comma-separated list of chalk colors to use on
prefixes. If there are more commands than colors, the
last color will be repeated.
- Available modifiers: reset, bold, dim, italic,
underline, inverse, hidden, strikethrough
- Available colors: black, red, green, yellow, blue,
magenta, cyan, white, gray, or any hex values for
colors, eg #23de43
- Available background colors: bgBlack, bgRed,
bgGreen, bgYellow, bgBlue, bgMagenta, bgCyan, bgWhite
See https://www.npmjs.com/package/chalk for more
information. [string] [default: "reset"]
-l, --prefix-length Limit how many characters of the command is displayed
in prefix. The option can be used to shorten the
prefix when it is set to "command"
[number] [default: 10]
-t, --timestamp-format Specify the timestamp in moment/date-fns format.
[string] [default: "yyyy-MM-dd HH:mm:ss.SSS"]

Input handling
-i, --handle-input Whether input should be forwarded to the child
processes. See examples for more information.[boolean]
--default-input-target Identifier for child process to which input on stdin
should be sent if not specified at start of input.
Can be either the index or the name of the process.
[default: 0]

Killing other processes
-k, --kill-others kill other processes if one exits or dies [boolean]
--kill-others-on-fail kill other processes if one exits with non zero status
code [boolean]

Restarting
--restart-tries How many times a process that died should restart.
Negative numbers will make the process restart forever.
[number] [default: 0]
--restart-after Delay time to respawn the process, in milliseconds.
[number] [default: 0]

Options:
-h, --help Show help [boolean]
-v, -V, --version Show version number [boolean]

Examples:

- Output nothing more than stdout+stderr of child processes

$ concurrently --raw "npm run watch-less" "npm run watch-js"

- Normal output but without colors e.g. when logging to file

$ concurrently --no-color "grunt watch" "http-server" > log

- Custom prefix

$ concurrently --prefix "{time}-{pid}" "npm run watch" "http-server"

- Custom names and colored prefixes

$ concurrently --names "HTTP,WATCH" -c "bgBlue.bold,bgMagenta.bold"
"http-server" "npm run watch"

- Send input to default

$ concurrently --handle-input "nodemon" "npm run watch-js"
rs # Sends rs command to nodemon process

- Send input to specific child identified by index

$ concurrently --handle-input "npm run watch-js" nodemon
1:rs

- Send input to specific child identified by name

$ concurrently --handle-input -n js,srv "npm run watch-js" nodemon
srv:rs

- Shortened NPM run commands

$ concurrently npm:watch-node npm:watch-js npm:watch-css

- Shortened NPM run command with wildcard

$ concurrently npm:watch-*

For more details, visit https://github.com/kimmobrunfeldt/concurrently
`

Programmatic Usage

concurrently can be used programmatically by using the API documented below:

$3

- commands: an array of either strings (containing the commands to run) or objects
with the shape { command, name, prefixColor, env, cwd }.
- options (optional): an object containing any of the below:
- cwd: the working directory to be used by all commands. Can be overriden per command.
Default: process.cwd().
- defaultInputTarget: the default input target when reading from inputStream.
Default: 0.
- inputStream: a Readable stream
to read the input from, eg process.stdin.
- killOthers: an array of exitting conditions that will cause a process to kill others.
Can contain any of success or failure.
- maxProcesses: how many processes should run at once.
- outputStream: a Writable stream
to write logs to. Default: process.stdout.
- prefix: the prefix type to use when logging processes output.
Possible values: index, pid, time, command, name, none, or a template (eg [{time} process: {pid}]).
Default: the name of the process, or its index if no name is set.
- prefixLength: how many characters to show when prefixing with command. Default: 10
- raw: whether raw mode should be used, meaning strictly process output will
be logged, without any prefixes, colouring or extra stuff.
- successCondition: the condition to consider the run was successful.
If first, only the first process to exit will make up the success of the run; if last, the last process that exits will determine whether the run succeeds.
Anything else means all processes should exit successfully.
- restartTries: how many attempts to restart a process that dies will be made. Default: 0.
- restartDelay: how many milliseconds to wait between process restarts. Default: 0.
- timestampFormat: a date-fns format
to use when prefixing with time. Default: yyyy-MM-dd HH:mm:ss.ZZZ

> Returns: a Promise that resolves if the run was successful (according to successCondition option),
> or rejects, containing an array of objects with information for each command that has been run, in the order
> that the commands terminated. The objects have the shape { command, index, exitCode, killed }, where command is the object
> passed in the commands array, index its index there and killed indicates if the process was killed as a result of
> killOthers. Default values (empty strings or objects) are returned for the fields that were not specified.

Example:

`js
const concurrently = require('concurrently');
concurrently([
'npm:watch-*',
{ command: 'nodemon', name: 'server' },
{ command: 'deploy', name: 'deploy', env: { PUBLIC_KEY: '...' } },
{ command: 'watch', name: 'watch', cwd: path.resolve(__dirname, 'scripts/watchers')}
], {
prefix: 'name',
killOthers: ['failure', 'success'],
restartTries: 3,
cwd: path.resolve(__dirname, 'scripts'),
}).then(success, failure);
`

FAQ

Process exited with code null*?

From Node child_process documentation, exit event:

> This event is emitted after the child process ends. If the process
> terminated normally, code is the final exit code of the process,
> otherwise null. If the process terminated due to receipt of a signal,
> signal is the string name of the signal, otherwise null.


So null means the process didn't terminate normally. This will make concurrent
to return non-zero exit code too.

* Does this work with the npm-replacements yarn or pnpm?

Yes! In all examples above, you may replace "npm" with "yarn" or "pnpm`".