feat: add completion script for bash

misc/igmpgen_completion.sh

@@ -0,0 +1,36 @@
+#!/bin/bash
+
+# Function for autocompletion
+_igmpgen_completion() {
+    local cur prev opts igmp_types
+    COMPREPLY=()   # Array variable storing the completions.
+    cur="${COMP_WORDS[COMP_CWORD]}"  # Current word being completed.
+    prev="${COMP_WORDS[COMP_CWORD-1]}"  # Previous word.
+
+    # Options for igmpgen
+    opts="-i -t -g -s -d -n"
+
+    # Available IGMP packet types
+    igmp_types="1.query 1.report 1.dvmrp 2.query 2.report 2.leave 3.report"
+
+    case "${prev}" in
+        -t)
+            COMPREPLY=( $(compgen -W "${igmp_types}" -- ${cur}) )
+            return 0
+            ;;
+    esac
+
+    # If the previous word is an option requiring an argument, don't complete with options
+    case "${prev}" in
+        -i | -g | -s | -d | -n)
+            return 0
+            ;;
+    esac
+
+    # Default completion: suggest igmpgen options
+    COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+}
+
+# Attach the completion function to igmpgen command
+complete -F _igmpgen_completion igmpgen
+