---
title: Exec Command
description: Learn more about the `exec` command in Melos.
---

# Exec Command

<Info>Supports all [Melos filtering](/filters) flags.</Info>

Execute an arbitrary command in each package.

```bash
melos exec
# e.g. melos exec -- pub global run tuneup check
```

The command is executed in a shell. On Windows the shell is `cmd.exe` and on all
other platforms it is `sh`.

If multiple commands are being executed and no further commands should be
executed after a command has failed, connect the commands with `&&`:

```shell
melos exec -- "melos bootstrap && melos run build"
```

It is important to pass multiple commands as a single string to `melos exec`,
otherwise the shell will pass only the first command to `melos exec`.

## concurrency (-c)

Defines the max concurrency value of how many packages will execute the command
in at any one time. Defaults to `5`.

```bash
# Set a 1 concurrency
melos exec -c 1  -- "dart analyze ."
```

## --fail-fast

Whether exec should fail fast and not execute the script in further packages if
the script fails in an individual package. Defaults to `false`.

```bash
# Fail fast
melos exec --fail-fast -- "dart analyze ."
```