> For the complete documentation index, see [llms.txt](https://docs.termius.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.termius.com/terminal/environment-variables.md).
# Environment variables
## Overview
Environment variables let you pass `KEY=VALUE` pairs to the remote shell as part of establishing an SSH connection. Termius sends them automatically on connect, using the same mechanism as OpenSSH's `SendEnv` client-side directive.
#### Example
```bash
LANG=en_US.UTF-8
APP_ENV=staging
```
{% hint style="info" %}
Environment variables can be set on both Hosts and Groups. When set on a Group, every Host inside the Group inherits that setting, see [Groups and tags](/organize-and-connect-to-hosts/groups-and-tags.md#how-hosts-inherit-group-properties).
{% endhint %}
## Accepted environment variables
To allow specific environment variables, list them after `AcceptEnv` keyword in the server's `sshd_config` (typically `/etc/ssh/sshd_config`). The `AcceptEnv` directives specify which client-sent variables are copied into the session's environment.
You can list one or more variable names after `AcceptEnv` keyword, and each name may contain the wildcards `*` and `?` to include groups of values. Multiple names can be separated by spaces on one line, or split across several `AcceptEnv` lines.
{% hint style="warning" %}
Some environment variables could be used to bypass restricted user environments, so `AcceptEnv` directives should be added deliberately rather than broadly. This is also why the default is to accept none at all.
{% endhint %}
#### Example
```bash
# sshd_config on the remote server
AcceptEnv LANG LC_* APP_ENV
```
With this configuration, only `LANG`, variables matching `LC_*` (e.g. `LC_TIME`, `LC_ALL`), and `APP_ENV` are accepted. Any other variable sent by Termius but not listed in `AcceptEnv` is silently dropped by `sshd`.
## Set an environment variables in Termius
1. Open the Host details, scroll to the credential section and click `Show more`
2. Click `Environment Variable`
3. Click `Add a variable`, add your variable as `VARIABLE(KEY)=VALUE`, then `Save`
4. To confirm the variable is set correctly, you can `echo` it once connected. If it prints the expected value, the variable is set. If it's empty, double-check that the variable name matches the `AcceptEnv` pattern in `sshd_config` , see [Accepted environment variables](#accepted-environment-variables) above
## Pro tip
Several hosts may run similar workloads with different service names. For example, some hosts may use `nginx`, while others use `gunicorn`. Let's assume you have snippets that restart each of these services. Instead of maintaining nearly identical snippets, you can set an environment variable for each Host and reference it in a [Snippet](/terminal/snippets.md):
1. On each Host, set the same variable name with its own value, see [#set-an-environment-variables](#set-an-environment-variables "mention"):
```bash
# Hosts: web-01, web-02, web-05
SERVICE_NAME=nginx
# Hosts: api-02, api-03
SERVICE_NAME=gunicorn
```
2. Create a `Snippet` that references the variable instead of a hardcoded service name:
```bash
sudo systemctl restart $SERVICE_NAME
```
3. Run the snippet on any of these Hosts. It restarts whichever service is actually correct on that machine: `nginx` on `web-01`, `gunicorn` on `api-02`
---
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