Is it possible to use a command with an argument to trigger a bash alias?

Question

I have a program that tries to trigger a screenlock using the following commands:

    xdg-screensaver lock
    xscreensaver -lock
    cinnamon-screensaver-command --lock

The problem is that I'm using Arch and I'm not using any of the screenlock programs listed above. I need one of the above commands to trigger my swaylock script.

Is it possible to use a command with an argument to trigger a bash alias? For example:
alias xscreensaver -lock="cd ~/.config/hypr/scripts && ./lockscreen"

There are a lot of posts about using functions to pass arguments, but I haven't been able to find any info on how to use an argument in the command that triggers the alias. I'm guessing this isn't possible, but maybe someone has some alternative suggestions to get the same effect.

Answer 1

"Programs" (as in "not scripts") usually don't parse users' RC files. So if your "program" is not a script that can be easily modifiable, most likely, it will inspect PATH to find the path to those executables, or it will check for the presence of those executables in specific paths.

If your program reads PATH to find the path to those executables, one way to go about this would be:

1. Creating a symlink to the script named as one of the executables, placing it into the same directory as the script's (or for that matter simply renaming the script as one of the executables)
2. Modifying the way the program is invoked, to provide it with a custom environment with a PATH that includes /home/<your_username>/config/hypr/scripts
3. No matter the options passed to the script, your script will just drop them and do whatever it wants.

As to how go about point #2 specifically: that depends on how your program is currently invoked. I can make this more specific depending on your case, but the general way to do this would be, instead of running program, running

env PATH="${PATH}:/home/<your_username>/config/hypr/scripts/" program

But this may or may not be applicable to your case, depending on how your program is invoked, and, again, depending on whether your program reads PATH to find the path to those executables.

---

This other way is rather a hack, and should be used only if the solution above isn't applicable, or if your program doesn't read PATH to find the path to those executables. See the caveat below.

Another way go about this, since you shouldn't have any of those executables installed on your system, would be:

1. Picking one of the unused executables, let's say xdg-screensaver;
2. Moving the script to the executable's path. On my system that would be /usr/bin/;
3. Taking care of owner and permissions, mirroring the default permissions of the executables. On my system, those would be root:root / 0755;

The obvious caveat is: this is ok as long as some other program doesn't try to rely on xdg-screensaver for something. Essentially, this may break other stuff, cause suddenly an already installed program (or a program you'll install in the future for that matter) might find an xdg-screensaver executable available for use and run it. Since I guess your script isn't a full drop-in replacement for xdg-screensaver, this may break the program trying to use it.

So, again, this is rather a hack, and should be used with care.

Answer 2

First a remark: I find it better to give this function a new name, different from existing commands.

Now the function:

xscrsave (){
    case "$1" in
    (-lock) cd ~/.config/hypr/scripts 
            ./lockscreen
            ;;
    (*)     xscreensaver "$@"
            ;;
}