[SOLVED] update a global variable in command_not_found

update a global variable in command_not_found_handler function in zshrc

I want to modify the command_not_found_handler function in zsh so that after execution, it prints the package installation command related to the command on the screen and stores its command in a global variable.

# this function provides command to install that packge if its not installed
command_not_found_handler() {
        cmd="$1"
        prt="zsh: command not found: $cmd"

        package=$(pacman -Ss "^$cmd$" | grep "/$cmd " | awk -F '/' '{print $2}' | cut -d' ' -f1)

        SUGGESTION_CMD="NOT FOUND"

        if [[ -n "$package" ]]; then
                SUGGESTION_CMD="pacman -S $package"
                prt="$prt ($SUGGESTION_CMD)\a"
        fi

        echo $prt

        return 127
}

export SUGGESTION_CMD

But after each execution of this function (if a command is entered and its package is not installed), the value of the variable is not updated globally.

$ gimp
zsh: command not found: gimp (pacman -S gimp)
$ echo $SUGGESTION_CMD

$ command_not_found_handler
zsh: command not found:
$ echo $SUGGESTION_CMD
NOT FOUND

I am a newbie myself and I also used chatgpt but I didn't get a response.

Solution

From the documentation (emphasis added):

Note that the handler is executed in a subshell forked to execute an external command, hence changes to directories, shell parameters, etc. have no effect on the main shell.

So what you're trying explicitly won't work. You might instead try using a file to hold the message instead and read its contents when needed elsewhere.