[Android Software Development] facuarmo:
Hey guys, I've just decided to get inside of the Android development world. Anyways, I'm mostly a fan of Linux, so I've made my first Linux script, I know it's simple, but I've never interacted with the user before, or picked an output. When I knew that Android made use of Linux in its core, my interest on working inside it grew up faster than ever.

In my script, firstly, you type the filename. For compatibility reasons, it'll everytime save to /sdcard/filename. Then, it will ask you how many times you want the script to log everything, and lately, every how many seconds should it save everything to the file.

The script will save, before every entry at the log, the screen status (if it's on or off), that can help to, for example, if your device has been lagging as a result of a bad screen driver or UI error.

Last thnig: it also works on recovery (maybe it give some error, and if no dumpsys is present on your recovery's ramdisk, it'll save everything as OFF).

Remember to send it anywhere excepting from /storage and any sbudir, it won't work as the Android permissions system blocks script execution on those dirs.

clear
# Wipe $logfile content in /sdcard (if any existing)
echo "Please type the filename where you want to save the log: "
read -r logfile
echo "" > /sdcard/$logfile
echo "Deleted previous log."
echo "SCREEN | CPU" >> /sdcard/$logfile
#cont=60
cont=1
#SHOWLOG=X
echo "Please type how many times the cycle must repeat: "
read -r maxcont
echo "Please type how many seconds will the interval take: "
read -r maxmin
clear
# Here it counts how many times the logging script has been ran
while [ $cont -lt $((maxcont + 1)) ];
do
# That nested while takes control of how many seconds have passed in the current cycle
while [ "$contmin" -lt "$maxmin" ];
do
contmin=$((contmin + 1))
sleep 1
clear
echo "C: $cont/$maxcont - T: $contmin/$maxmin"
done
# echo "$maxmin seconds passed."
# Logs the fist line of "busybox top" to a var
LOGVAR=$(busybox top -d 1 -n 1 | grep "idle")
# Logs the screen state (on or off) to another var
SCREENSTATE=$(dumpsys input_method | grep mScreenOn | tr -dc '[:alnum:]\n\r' | tr '[:upper:]' '[:lower:]')
# Saves a string that tells what it should expect if the screen is on
SCREENSTATEON="msystemreadytruemscreenontrue"
if [ "$SCREENSTATE" == "$SCREENSTATEON" ]
then
echo "ON: $LOGVAR" >> /sdcard/$logfile
else
echo "OFF: $LOGVAR" >> /sdcard/$logfile
fi
cont=$((cont + 1))
contmin=0
done
echo "Show logged values? [Y/N]"
read -r SHOWLOG
case $SHOWLOG in

[yY] | [yY][Ee][Ss] )
cat /sdcard/$logfile
;;

[nN] | [n|N][O|o] )
echo "Ok, goodbye. You'll see a what you've asked me to log in /sdcard/$logfile";
exit 1
;;
*) echo "You must write Y or N to continue."
;;
esac
exit 0

For example, save it as script.sh (remember to save it using Unix codifcation, if you're running Windows, else, it'll tell you that it's unable to find many binaries, as long as Linux isn't ok with CR+LF and requires LF as newline). Then, send it to the sdcard (over USB or adb push script.sh /sdcard/) , now, run ADB shell. Type the following commands:

su -c "cp -f /sdcard/script.sh /data/local/;chmod 777 /data/local/script.sh"

Then, if you want to run it:

su
sh /data/local/script.sh

That's all, I hope you enjoy it and not so many people kills me for explaining and feeling so grateful for that simple script.