Bash script to record screenshots on Android until interrupted, then assemble all screenshots to an animated GIF. Useful for demos etc. Requires ImageMagick's (convert) to be on your path.

android-screen-gif.sh

#!/bin/sh

PREFIX="Screenshot-$(date +%Y%m%d-%H%M%S)"
BASE="/sdcard/$PREFIX"
DELAY=300

trap ctrl_c INT

function clean_up() {
  rm -f $PREFIX*.png
  echo "Cleaned up individual screenshots."
  adb $1 $2 shell rm -rf $BASE
}

function pull_images() {
  echo "Downloading images."
  adb $1 $2 pull "$BASE/"
}

function assemble_gif() {
  for image in $PREFIX/*.png; do
    if [[ $(identify -quiet $image) ]]; then
      echo "Valid image $image"
    else
      echo "Invalid image file $image, deleting"
      rm -f $image
    fi
  done
  convert -delay $DELAY -loop 0 "$PREFIX/*.png" $PREFIX.gif
  echo "Assembled gif $PREFIX.gif"
}

running=1
function ctrl_c() {
  echo "Will clean up"
  running=-1
}

adb shell mkdir $BASE
i=0
while [ $running -ge 0 ]
do
 i=$(($i+1))
 IMAGE="$BASE/$PREFIX-$i.png"
 adb $1 $2 shell screencap -p $IMAGE
 echo "Wrote screenshot to $IMAGE"
done

pull_images
assemble_gif
clean_up
open $PREFIX.gif

I tried to run it by saying "./android-screen-gif.sh" and"sh android-screen-gif.sh"
It gives me an error saying "Permission denied" in the first case and "device not found" in the second
I also changed the permissions and tried to run it, no difference.
I tried placing the script file in both sdcard and external_sd directories and running it. No difference.
I copy pasted the script file into my phone. Should I modify it in any way to match my phone?
My phone is Samsung Galaxy S4, GT i9500. I'm using GearCM12.1 rom, debugging is enabled, phone is rooted.
How do I run this script? Please help

The script runs on your computer, not your device.
Simply put it in a folder on your machine, chmod +x android-screen-gif.sh and ./android-screen-gif.sh
You'll also need to install the ImageMagick to your path (convert).

However, it looks like you're using a Windows machine which means you're out of luck for running shell scripts, sorry about that (buy a Mac :) ).

find: Screenshot-20160323-125825*.png': No such file or directory convert.im6: unable to open imageScreenshot-20160323-125825_.png': No such file or directory @ error/blob.c/OpenBlob/2638.
convert.im6: unable to open file Screenshot-20160323-125825_.png' @ error/png.c/ReadPNGImage/3667. convert.im6: no images defined Screenshot-20160323-125825.gif' @ error/convert.c/ConvertImageCommand/3044.
Assembled gif Screenshot-20160323-125825.gif
Cleaned up individual screenshots.
Couldn't get a file descriptor referring to the console