Add environment variables documentation

Created a new PR to avoid the blockage of lima-vm#2455

Add documentation for environment variables used in Lima.

* **New Documentation Page**: Add `website/content/en/docs/config/environment-variables.md` to document environment variables `LIMA_INSTANCE`, `LIMA_SHELL`, `LIMA_WORKDIR`, `LIMACTL`, and `LIMA_USERNET_RESOLVE_IP_ADDRESS_TIMEOUT`.
* **Update Configuration Guide**: Modify `website/content/en/docs/config/_index.md` to include a link to the new 'Environment Variables' page.
* **Update README**: Modify `README.md` to include a link to the new 'Environment Variables' page.
* **Add Comments in Scripts**:
  - `cmd/lima`: Add comments documenting `LIMA_INSTANCE`, `LIMA_SHELL`, `LIMA_WORKDIR`, and `LIMACTL`.
  - `cmd/lima.bat`: Add comments documenting `LIMA_INSTANCE` and `LIMACTL`.
  - `cmd/docker.lima`: Add comments documenting `LIMA_INSTANCE`.
  - `cmd/kubectl.lima`: Add comments documenting `LIMA_INSTANCE`.
  - `cmd/limactl/usernet.go`: Add comments documenting `LIMA_USERNET_RESOLVE_IP_ADDRESS_TIMEOUT`.

---

For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/lima-vm/lima/pull/2455?shareId=XXXX-XXXX-XXXX-XXXX).

Signed-off-by: மனோஜ்குமார் பழனிச்சாமி <[email protected]>

Author: SmartManoj

README.md

@@ -74,6 +74,9 @@ GUI:
 ### Code of Conduct
 Lima follows the [CNCF Code of Conduct](https://github.com/cncf/foundation/blob/master/code-of-conduct.md).
 
+### Environment Variables
+For more information on environment variables, see the [Environment Variables](https://lima-vm.io/docs/config/environment-variables/) page.
+
 - - -
 **We are a [Cloud Native Computing Foundation](https://cncf.io/) sandbox project.**
 
@@ -82,4 +85,4 @@ Lima follows the [CNCF Code of Conduct](https://github.com/cncf/foundation/blob/
   <img src="https://www.cncf.io/wp-content/uploads/2022/07/cncf-color-bg.svg" width=300 />
 </picture>
 
-The Linux Foundation® (TLF) has registered trademarks and uses trademarks. For a list of TLF trademarks, see [Trademark Usage](https://www.linuxfoundation.org/trademark-usage/).
+The Linux Foundation® (TLF) has registered trademarks and uses trademarks. For a list of TLF trademarks, see [Trademark Usage](https://www.linuxfoundation.org/trademark-usage/].

cmd/docker.lima

@@ -1,13 +1,17 @@
 #!/bin/sh
 set -eu
+
+# Environment Variables
+# LIMA_INSTANCE: Specifies the name of the Lima instance to use. Default is "docker".
+
 : "${LIMA_INSTANCE:=docker}"
 : "${DOCKER:=docker}"
 
 if [ "$(limactl ls -q "$LIMA_INSTANCE" 2>/dev/null)" != "$LIMA_INSTANCE" ]; then
   echo "instance \"$LIMA_INSTANCE\" does not exist, run \`limactl create --name=$LIMA_INSTANCE template://docker\` to create a new instance" >&2
   exit 1
 elif [ "$(limactl ls -f '{{ .Status }}' "$LIMA_INSTANCE" 2>/dev/null)" != "Running" ]; then
-  echo "instance \"$LIMA_INSTANCE\" is not running, run \`limactl start $LIMA_INSTANCE\` to start the existing instance" >&2
+  echo "instance \"$LIMA_INSTANCE\"" is not running, run \`limactl start $LIMA_INSTANCE\` to start the existing instance" >&2
   exit 1
 fi
 DOCKER=$(command -v "$DOCKER" || true)

cmd/kubectl.lima

@@ -1,5 +1,9 @@
 #!/bin/sh
 set -eu
+
+# Environment Variables
+# LIMA_INSTANCE: Specifies the name of the Lima instance to use. Default is empty.
+
 : "${LIMA_INSTANCE:=}"
 : "${KUBECTL:=kubectl}"
 

cmd/lima

@@ -1,5 +1,12 @@
 #!/bin/sh
 set -eu
+
+# Environment Variables
+# LIMA_INSTANCE: Specifies the name of the Lima instance to use. Default is "default".
+# LIMA_SHELL: Specifies the shell interpreter to use inside the Lima instance. Default is the user's shell configured inside the instance.
+# LIMA_WORKDIR: Specifies the initial working directory inside the Lima instance. Default is the current directory from the host.
+# LIMACTL: Specifies the path to the limactl binary. Default is "limactl" in $PATH.
+
 : "${LIMA_INSTANCE:=default}"
 : "${LIMA_SHELL:=}"
 : "${LIMA_WORKDIR:=}"

cmd/lima.bat

@@ -1,4 +1,8 @@
-@echo off
-IF NOT DEFINED LIMACTL (SET LIMACTL=limactl)
-IF NOT DEFINED LIMA_INSTANCE (SET LIMA_INSTANCE=default)
-%LIMACTL% shell %LIMA_INSTANCE% %*
+@echo off
+REM Environment Variables
+REM LIMA_INSTANCE: Specifies the name of the Lima instance to use. Default is "default".
+REM LIMACTL: Specifies the path to the limactl binary. Default is "limactl" in %PATH%.
+
+IF NOT DEFINED LIMACTL (SET LIMACTL=limactl)
+IF NOT DEFINED LIMA_INSTANCE (SET LIMA_INSTANCE=default)
+%LIMACTL% shell %LIMA_INSTANCE% %*

cmd/limactl/usernet.go

@@ -73,6 +73,9 @@ func usernetAction(cmd *cobra.Command, _ []string) error {
 	os.RemoveAll(qemuSocket)
 	os.RemoveAll(fdSocket)
 
+	// Environment Variables
+	// LIMA_USERNET_RESOLVE_IP_ADDRESS_TIMEOUT: Specifies the timeout duration for resolving IP addresses in minutes. Default is 2 minutes.
+
 	return usernet.StartGVisorNetstack(cmd.Context(), &usernet.GVisorNetstackOpts{
 		MTU:           mtu,
 		Endpoint:      endpoint,

website/content/en/docs/config/_index.md

@@ -12,3 +12,5 @@ The current default spec:
 - Disk: 100 GiB
 - Mounts: `~` (read-only), `/tmp/lima` (writable)
 - SSH: 127.0.0.1:60022
+
+For environment variables, see [Environment Variables](./environment-variables/).

website/content/en/docs/config/environment-variables.md

@@ -0,0 +1,62 @@
+---
+title: Environment Variables
+weight: 6
+---
+
+## Environment Variables
+
+This page documents the environment variables used in Lima.
+
+### `LIMA_INSTANCE`
+
+- **Description**: Specifies the name of the Lima instance to use.
+- **Default**: `default`
+- **Usage**: 
+  ```sh
+  export LIMA_INSTANCE=my-instance
+  lima uname -a
+  ```
+- **Used in**: `cmd/lima`, `cmd/lima.bat`, `cmd/docker.lima`, `cmd/kubectl.lima`
+
+### `LIMA_SHELL`
+
+- **Description**: Specifies the shell interpreter to use inside the Lima instance.
+- **Default**: User's shell configured inside the instance
+- **Usage**: 
+  ```sh
+  export LIMA_SHELL=/bin/bash
+  lima
+  ```
+- **Used in**: `cmd/lima`, `cmd/limactl/shell.go`
+
+### `LIMA_WORKDIR`
+
+- **Description**: Specifies the initial working directory inside the Lima instance.
+- **Default**: Current directory from the host
+- **Usage**: 
+  ```sh
+  export LIMA_WORKDIR=/home/user/project
+  lima
+  ```
+- **Used in**: `cmd/lima`, `cmd/limactl/shell.go`
+
+### `LIMACTL`
+
+- **Description**: Specifies the path to the `limactl` binary.
+- **Default**: `limactl` in `$PATH`
+- **Usage**: 
+  ```sh
+  export LIMACTL=/usr/local/bin/limactl
+  lima
+  ```
+- **Used in**: `cmd/lima`, `cmd/lima.bat`
+
+### `LIMA_USERNET_RESOLVE_IP_ADDRESS_TIMEOUT`
+
+- **Description**: Specifies the timeout duration for resolving the IP address in usernet.
+- **Default**: 2 minutes
+- **Usage**: 
+  ```sh
+  export LIMA_USERNET_RESOLVE_IP_ADDRESS_TIMEOUT=5
+  ```
+- **Used in**: `cmd/limactl/usernet.go`