Add simple bash_completion script

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>

Makefile

@@ -2,7 +2,9 @@ check:
 	bash -n update-kernel
 	bash -n remove-old-kernels
 	bash -n analyze-kmodules
+	bash -n bash_completion
 	shellcheck -x update-kernel remove-old-kernels analyze-kmodules
+	shellcheck -s bash bash_completion
 
 docker-build:
 	docker build .

bash_completion

@@ -0,0 +1,50 @@
+# bash completion for update-kernel                        -*- shell-script -*-
+# shellcheck disable=SC2207,SC2155
+
+_update_kernel()
+{
+    # shellcheck disable=SC2034
+    local cur prev words cword
+    _init_completion || return
+
+    local cmd=${1##*/}
+
+    case $prev in
+        -t | --type)
+            # shellcheck disable=SC2034
+            local flavours="
+                ovz-el7
+                std-def
+                std-kvm
+                un-def
+            "
+            COMPREPLY=( $(compgen -W "\$flavours" -- "$cur" | sort ) )
+            return
+            ;;
+        -A)
+            return
+            ;;
+        -r | --release)
+            return
+            ;;
+    esac
+
+    if [[ $cur == -* ]]; then
+        local script="/usr/sbin/$cmd"
+
+        if [ -f "$script" ]; then
+            local short=$(LC_ALL=C grep -oP 'getopt.*-o \K[^\s]+' "$script" | sed -E 's/://g; s/(^|,)/\n-/g')
+            local  long=$(LC_ALL=C grep -oP 'getopt.*-l \K[^\s]+' "$script" | sed -E 's/://g; s/(^|,)/\n--/g')
+            # shellcheck disable=SC2034
+            local  opts=$(LC_ALL=C echo "$short $long" | sort)
+            COMPREPLY=($( compgen -W "\$opts" -- "$cur") )
+        else
+            # Fallback
+            COMPREPLY=($( compgen -W "\$(_parse_help $1)" -- "$cur") )
+        fi
+    fi
+
+} &&
+    complete -F _update_kernel update-kernel remove-old-kernels
+
+# ex: filetype=sh sw=4 et