slopspawn.sh

#!/usr/bin/env bash
# depends: dmenu slop xdotool
# assumes next spawned window will be floating/moveable by xdotool.

# get program name to launch using dmenu cache:
cachedir=${XDG_CACHE_HOME:-"$HOME/.cache"}
if [ -d "$cachedir" ]; then
	cache=$cachedir/dmenu_run
else
	cache=$HOME/.dmenu_cache # if no xdg dir, fall back to dotfile in ~
fi
program=$(
	IFS=:
	if stest -dqr -n "$cache" $PATH; then
		stest -flx $PATH | sort -u | tee "$cache" | dmenu "$@"
	else
		dmenu "$@" < "$cache"
	fi
)

# Set dimension vars with slop
eval `slop`

# Get current window
win=`xdotool getactivewindow`

# bspwm specific, force next floating:
bspc rule -a \* --one-shot floating=true

$program &

# Wait for window to spawn and move with xdotool.
newwin=$win
while [ "$newwin" = "$win" ]; do
	newwin=`xdotool getactivewindow`
done

xdotool windowmove $newwin $X $Y
xdotool windowsize $newwin $W $H

https://www.reddit.com/r/unixporn/comments/3m58zw/script_wm_independent_slop_program_spawn/