Check out example codes for "Using shell script, display the contents of the present working directory. If it is an ordinary file print its permission and change the permissions to r--r--r--". It will help you in understanding the concepts better.

Code Example 1

# !/bin/bash

for item in *
do
  if [ -f $item ]
then
echo "----------------$item----------------"
if [ -x $item ]
then
echo "File in Executable mode"
chmod -x $item
echo "Executable permission Removed!"
  fi
if [ -w $item ]
then
echo "File in Write mode"
chmod -w $item
echo "Write permission Removed!"
fi
  if [ -r $item ]
then
echo "Already in read mode(r--r--r--)"
else
chmod +r $item
echo "Now the read permission granted "
  fi
echo "final permission"
ls -al $item
fi
echo
done

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