feat: add documentation for adding new commands

Author: MicLieg

SUMMARY.md

@@ -10,6 +10,7 @@
 * [Test Environment](getting-started/test-environment.md)
 * [Developer Commands](getting-started/developer-commands.md)
 * [Adding a new Game Server](getting-started/adding-a-new-game-server.md)
+* [Adding a new Command](getting-started/adding-a-new-command.md)
 
 ## Workflow
 

getting-started/adding-a-new-command.md

@@ -0,0 +1,143 @@
+# Adding a new Command
+
+Adding new [commands](https://dev-docs.linuxgsm.com/technical/commands) to LinuxGSM is easier than you think and can be done in a few simple steps by following the instructions below.
+
+## Create new command script
+
+The first step is to create a new script in the `lgsm/modules` directory. The script should be named `command_[commandname].sh`, where `[commandname]` is the name of the command you want to add.
+
+For example `lgsm/modules/command_hello_world.sh`:
+
+```bash
+#!/bin/bash
+# LinuxGSM command_hello_world.sh module
+# Author: Daniel Gibbs
+# Contributors: http://linuxgsm.com/contrib
+# Website: https://linuxgsm.com
+# Description: Example Hello World command.
+
+commandname="HELLO-WORLD"                                          # Identifies the command in code
+commandaction="Hello World"                                        # Tells the user which command is running
+moduleselfname="$(basename "$(readlink -f "${BASH_SOURCE[0]}")")"  # Used to get the filename of the current script
+fn_firstcommand_set                                                # Track the first command executed
+
+check.sh                                                           # Used to perform a variety of checks
+
+# Place your code here
+fn_print_info_nl "Hello World!"                                    # Print to console
+fn_script_log_info "Hello World!"                                  # Log output of the script to the LinuxGSM log
+
+core_exit.sh                                                       # Used to exit the script
+```
+
+## Add neccessary checks
+
+You should ensure that any necessary [checks](https://dev-docs.linuxgsm.com/technical/checks) are run before or during the execution of the command. This is to ensure that the command (or parts of the command) can only be executed if the server is in a state where the command can do its job.
+
+To do this, you need to add your command name to the `allowed_commands_array` in `lgsm/modules/check.sh` for each check you want LinuxGSM to perform.
+
+Some Examples:
+
+- The check `check_logs.sh` is needed by almost every command to check if log files exist:
+
+```bash
+allowed_commands_array=([...] HELLO-WORLD [...])
+for allowed_command in "${allowed_commands_array[@]}"; do
+    if [ "${allowed_command}" == "${commandname}" ]; then
+        check_logs.sh
+    fi
+done
+```
+
+- You may want to check that the server is running before your command does anything:
+
+```bash
+allowed_commands_array=([...] HELLO-WORLD [...])
+for allowed_command in "${allowed_commands_array[@]}"; do
+    if [ "${allowed_command}" == "${commandname}" ]; then
+        check_status.sh
+    fi
+done
+```
+
+- You can also run checks directly in your command script:
+
+```bash
+[...]
+
+check_status.sh
+if [ "${status}" == "1" ]; then
+    fn_print_info_nl "Server Online"
+else
+    fn_print_info_nl "Server Offline"
+fi
+
+
+# Place your code here
+fn_print_info_nl "Hello World!"                                    # Print to console
+fn_script_log_info "Hello World!"                                  # Log output of the script to the LinuxGSM log
+
+core_exit.sh                                                       # Used to exit the script
+```
+
+### Adding custom checks
+
+If you need to add a custom check, you can do so by creating a new check script in `lgsm/modules` and using it either directly in your command script or by adding it to `lgsm/modules/check.sh` as shown above.
+
+## Add your command to the list of commands
+
+Now you need to have a look at the file `lgsm/modules/core_getopt.sh` and add your command to the list of commands. To do this, follow these last 2 steps:
+
+### Add a new command array
+
+This array should contain the following information
+
+- `User commands` - The commands (short form & long form) that the user can type to run the command
+- `Trigger comands` - The filename of the command
+- `Description` - A short description of the command
+
+For example:
+
+```bash
+cmd_hello_world=("hw;hello-world" "command_hello_world.sh" "Print Hello World!")
+```
+
+### Add the command array to the list of commands
+
+Append the command array to the list of commands called `currentopt`. Do this wherever you think it makes sense. If your command has any conditions (e.g. only available for certain games), you should check for these conditions before adding the command to the list.
+
+Some examples:
+
+- If you want to make the command available for the game `examplegame`(`eg`):
+
+```bash
+# Hello World exclusive.
+if [ "${shortname}" == "eg" ]; then
+	currentopt+=("${cmd_hello_world[@]}")
+fi
+```
+
+- If you want to make the command available for multiple games `examplegame`(`eg`) & `helloworldgame`(`hwg`):
+
+```bash
+# Hello World for examplegame and helloworldgame.
+if [ "${shortname}" == "eg" ] || [ "${shortname}" == "hwg" ]; then
+	currentopt+=("${cmd_hello_world[@]}")
+fi
+```
+
+- If you want to make the command available for all games that use a particular game engine (e.g. `source'):
+
+```bash
+# Hello World for source engine games
+if [ "${engine}" == "source" ]; then
+    currentopt+=("${cmd_hello_world[@]}")
+fi
+```
+
+- If you want to make the command available for all games
+
+```bash
+# Hello World
+currentopt+=("${cmd_hello_world[@]}")
+```

getting-started/adding-a-new-game-server.md

@@ -70,5 +70,5 @@ Not all game servers use SteamCMD. If this is the case a custom update module wi
 
 ## Custom Commands
 
-Some game servers may require bespoke commands to complete tasks. Examples of this include Teamspeak 3 and Unreal Tournament 2004. Take a look at the `core_getopts.sh` module for examples of how to add commands.
+Some game servers may require bespoke commands to complete tasks. Examples of this include Teamspeak 3 and Unreal Tournament 2004. Take a look at [Adding a new command](https://dev-docs.linuxgsm.com/getting-started/adding-a-new-command) for examples of how to add new commands.