---
name: "jexec"
section: "8"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/jexec"
---

# jexec(8)

execute a command inside an existing jail

## NAME

**jexec** – execute a command inside an existing jail

## SYNOPSIS

**jexec** \[**-l**\] \[**-d** *working-directory*\] \[\[**-e** *name*=*value*\] ...\] \[**-u** *username* \| **-U** *username*\] *jail* \[*command* *...*\]

## DESCRIPTION

The **jexec** utility executes *command* inside the *jail* identified by its jid or name. If *command* is not specified then the user's shell is used.

The following options are available:

- **-d** *working-directory*

  The working directory for running commands inside the jail. The default is the jail root directory.

- **-l**

  Execute in a clean environment. The environment is discarded except for HOME, SHELL, TERM, USER, and anything from the login class capability database for the user. PATH is set to "/bin:/usr/bin". If a user is specified (via **-u** or **-U**), and absent the **-d** option, commands are run from that (possibly jailed) user's directory.

- **-e** *name*=*value*

  Set environment variables.

  This parameter allows arbitrary environment variables that are available to the process to be executed inside of the jail, overwriting any previously defined environment variables, such as those specified by the **-l** parameter.

  This option can be set multiple times.

- **-u** *username*

  The user name from host environment as whom the *command* should run. This is the default.

- **-U** *username*

  The user name from jailed environment as whom the *command* should run.

## EXAMPLES

### Example 1 : Open a shell in a jail

The following command specifies a jail by its name and utilizes the current user's shell:

```
# jexec name
```

It is also possible to specify a jail by its jid:

```
# jexec JID
```

### Example 2 : Run a single command without opening a shell

The following command runs ‘uname -a’ in a jail called “name”. Since a command is specified explicitly, **jexec** does not spawn an interactive shell. Instead, **jexec** executes the specified command directly.

```
# jexec name uname -a
```

### Example 3 : Open a shell in a jail with a clean environment

The following command opens a [sh(1)](/sh/1.md) shell in a jail with a clean environment:

```
# jexec -l name sh
```

### Example 4 : Open a shell in a jail with the login command

The following command utilizes [login(1)](/login/1.md) to access the jail, submitting an audit record, and displaying the user's last login, system copyright, and [motd(5)](/motd/5.md) message:

```
# jexec -l name login -f root
```

## SEE ALSO

[jail\_attach(2)](/jail_attach/2.md), [jail(8)](/jail/8.md), [jls(8)](/jls/8.md)

## HISTORY

The **jexec** utility was added in FreeBSD 5.1.

## BUGS

If the jail is not identified by *jid* there is a possible race in between the lookup of the jail and executing the command inside the jail. Giving a *jid* has a similar race as another process can stop the jail and start another one after the user looked up the *jid*.