read write permissions code example

Example 1: 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--

# !/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

Example 2: linux chmod permissions

The three rightmost digits define permissions for the:
file user, the group, and others. 

#	Permission				rwx	Binary
7	read, write and execute	rwx	111
6	read and write			rw-	110
5	read and execute		r-x	101
4	read only				r--	100
3	write and execute		-wx	011
2	write only				-w-	010
1	execute only			--x	001
0	none					---	000