Android screenshot to current dir

screenshot_android.sh

#!/bin/bash

while getopts y: flag
do
    case "${flag}" in
        y) size=${OPTARG};;
    esac
done

DEVICES=`adb devices | grep -v devices | grep device | cut -f 1`
for device in $DEVICES; do
	output="screen_$(echo $device)_$(date +%Y%m%d_%H%M%S).png"
    echo "Capturing from $device"
    adb -s $device shell screencap -p /sdcard/screen.png
    adb -s $device pull /sdcard/screen.png $output
    adb -s $device shell rm /sdcard/screen.png

    if [ ! -z $size ] 
	then 
	    sips -Z $size $output
	fi
    
done

Thanks for the script!
I've modified it a bit to suit my need (working with devices with multiple screens like the Samsung Z Fold):

#!/bin/bash

while getopts y: flag
do
    case "${flag}" in
        y) size=${OPTARG};;
    esac
done

DEVICES=`adb devices | grep -v devices | grep device | cut -f 1`
for device in $DEVICES; do
    DISPLAYS=`adb -s $device shell dumpsys SurfaceFlinger --display-id | cut -d" " -f 2`
    for display in $DISPLAYS; do
        echo "Capturing from $display on $device"
        output="screen_$(echo $device)_$(echo $display)_$(date +%Y%m%d_%H%M%S).png"
        adb -s $device exec-out screencap -p -d $display > $output

        if [ ! -z $size ]; then 
	        sips -Z $size $output
	    fi
    done
done

BTW: Using exec-out you can avoid to generate the file on the device and then copy/delete it.