maim.sh

#!/usr/bin/env bash

# Find an unused file name to capture to
DIR=~/Pictures/Screenshots/
N=1
while [ -f "$DIR`printf %05d $N`.png" ]; do
    N=$((N+1))
done

FILENAME=$DIR`printf %05d $N`.png

# Take screenshot, if successful copy to clipboard and show notification
if maim -s > $FILENAME; then
    xclip -selection clip -target image/png < $FILENAME
    notify-send "Screenshot saved" $FILENAME
fi

line 4 should be "DIR=~/Pictures/Screenshots/" so that everyone can take your script and use it without the need to modify the home path

@afarazit Actually that does not work since it takes a literal ~ instead of expanding it. However if you remove the quotes then it works. I'll change the gist.