now running kernel version is detected and the right package gets selected automatically

modprobe_old_kernel.sh

 #!/usr/bin/env fish
 
-# fancy select kernel version
-set kernel_pkg (ls -1 /var/cache/pacman/pkg/linux* | grep -E '(.*)linux[[:digit:]]+-[[:digit:]]+(.*)' | fzf)
+# fancy select kernel versionx
+set cur_ver (uname -r | string match -rg "(\d+\.\d+\.\d+-\d+)")
+echo -n Detected kernel version' '; set_color brgreen; echo $cur_ver; set_color normal
+
+set kernel_pkg                                                                \
+(: 'list all packages in cache')                                              \
+  (ls -1 /var/cache/pacman/pkg/linux*                                         \
+(: 'filter by `is-linux-kernel` _and_ `matches-current-kernel`')              \
+ | grep -E '(.*)linux[[:digit:]]+-'$cur_ver'(.*)'                             \
+(: 'filter out the signature file')                                           \
+ | grep -vE '.sig'                                                            \
+(: 'and prompt')                                                              \
+ | fzf)
 # even fancier select kernel version
 #set kernel_pkg (ls -1 | grep "linux-"(string replace "-MANJARO" "" (uname -r))