This script reverses a string and compares it with the original string to see whether it is a palindrome or not.
To reverse a string, a for loop is used that iterates the bash facility to take substrings. It takes the ith character of the given string, and prepends it to the variable that we use to store the reverse of it. Finally, it can be compared with the original string to see whether it is a palindrome or not.
Code
#!/bin/bash
echo -n "Enter a string: "
read str
for i in $(seq 0 ${#str}) ; do
revstr=${str:$i:1}$revstr
done
echo "The given string is " $str
echo "Its reverse is " $revstr
if [ "$str" = "$revstr" ]; then
echo "It is a palindrome."
else
echo "It is not a palindrome."
fiIn the above code, we have used an expression ${str:$i:1}, which simply means take one character from the ith position. revstr=${str:$i:1}$revstr means revstr becomes this new character + the old revstr.
Keywords (click to browse): palindrome reverse string shell sh bash linux gnu unix script programming command-line
