adb shell rm

remove files or directories

rm [options] <files or directory>

STEP 1.

adb shell

STEP 2.

rm /sdcard/test.txt

rm -f /sdcard/test.txt force remove without prompt
rm -r /sdcard/tmp remove the contents of directories recursively
rm -d /sdcard/tmp remove directory, even if it is a non-empty directory
Notes: rm -d equal rmdir command
rm -i /sdcard/test.txt prompt before any removal