# LibTmux::Server::unset_environment

- **Module:** LibTmux
- **Package:** LibTmux
- **Language:** Perl
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-perl/blob/352715a4fa66a96eed7763b90daaa536aa2f121d/packages/core/lib/LibTmux/Server.pm#L1108
- **Page:** https://libtmux.org/en/perl/latest/reference/libtmux-server-unset_environment/

```
sub unset_environment($self, %args)
```

`unset_environment(name => env_name, session => session_target?)`.

Unset the named session/global variable. This differs from setting an empty value; [`"get_environment"`](/en/perl/latest/reference/libtmux-server-get_environment/) reports the unset state as a command error.

Returns `undef` after command acceptance. Performs I/O; failures propagate through [`LibTmux::X`](/en/perl/latest/reference/libtmux-x/). Captured objects are not modified.


```perl
    $server->unset_environment(session => $session, name => 'BUILD');
```

## Methods

## Parameters

- `args`

## tmux command

The tmux commands behind `unset_environment`.

- [`set-environment`](/en/tmux/latest/manual/set-environment/)

## tmux C API

The C declarations in tmux that implement these commands.

- [`cmd_set_environment_entry`](/en/tmux/latest/reference/c-variable-cmd_set_environment_entry/) (attribute)
- [`cmd_set_environment_exec`](/en/tmux/latest/reference/c-function-cmd-set-environment-c-cmd_set_environment_exec/) (function)

## In other ports

Unset a variable in the server's environment

| Language | Equivalent |
| --- | --- |
| Python | [`libtmux.Server.unset_environment`](/en/py/latest/reference/libtmux-server-unset_environment/) (method) |
| Ruby | [`LibTmux::Server#unset_environment`](/en/ruby/latest/reference/libtmux-server-unset_environment/) (method) |
| Lua | [`libtmux.Server:unset_environment`](/en/lua/latest/reference/libtmux-server-unset_environment/) (method) |
| Haskell | No public Haskell equivalent is implemented; the current modules expose scalar values and version parsing. |
| TypeScript | [`server.Server.unsetEnvironment`](/en/ts/latest/reference/server-server-unsetenvironment/) (method) |
| Rust | [`server.Server.unset_environment`](/en/rs/latest/reference/server-server-unset_environment/) (method) |
| Go | [`tmux.Server.UnsetEnvironment`](/en/go/latest/reference/tmux-server-unsetenvironment/) (method) |
| Java | no equivalent on `Server` |
| C# | no equivalent on `Server` |
| C++ | no equivalent on `Server` |
| Swift | [`Server.unsetEnvironment(_:in:)`](/en/swift/latest/reference/server-unsetenvironment(_-in-)/) (method) |
| OCaml | [`Libtmux_unix.Client.unset_environment`](/en/ocaml/latest/reference/libtmux_unix-client-unset_environment/) (function) |

No equivalent is recorded in PowerShell, Julia, Erlang, Elixir, Common Lisp, Clojure, Kotlin, Scala or F#.

Unset a variable in a session's environment

| Language | Equivalent |
| --- | --- |
| Python | [`libtmux.Session.unset_environment`](/en/py/latest/reference/libtmux-session-unset_environment/) (method) |
| Ruby | [`LibTmux::Session#unset_environment`](/en/ruby/latest/reference/libtmux-session-unset_environment/) (method) |
| Lua | [`libtmux.Session:unset_environment`](/en/lua/latest/reference/libtmux-session-unset_environment/) (method) |
| Haskell | No public Haskell equivalent is implemented; the current modules expose scalar values and version parsing. |
| TypeScript | [`session.Session.unsetEnvironment`](/en/ts/latest/reference/session-session-unsetenvironment/) (method) |
| Rust | [`session.Session.unset_environment`](/en/rs/latest/reference/session-session-unset_environment/) (method) |
| Go | [`tmux.Session.UnsetEnvironment`](/en/go/latest/reference/tmux-session-unsetenvironment/) (method) |
| Java | no equivalent on `Session` |
| C# | no equivalent on `Session` |
| C++ | no equivalent on `Session` |
| Swift | [`Server.unsetEnvironment(_:in:)`](/en/swift/latest/reference/server-unsetenvironment(_-in-)/) (method) |
| OCaml | [`Libtmux_unix.Client.unset_environment`](/en/ocaml/latest/reference/libtmux_unix-client-unset_environment/) (function) |

No equivalent is recorded in PowerShell, Julia, Erlang, Elixir, Common Lisp, Clojure, Kotlin, Scala or F#.