Comparing two string variables in bash-CodePudding

This block of code keeps echoing "they are equal" Why?

#!/bin/bash

foo="hello"
bar="h"
if [[ "$foo"=="$bar" ]]; then
        echo "they are equal"
else
        echo "they are not equal"
fi

CodePudding user response：

The condition works based on the number of elements within it, and this particular issue is covered by this (paraphrased) part of the man-page:

string: True if the length of string is non-zero.

string1 == string2: True if the strings are equal.

In other words, a comparison needs three elements, meaning you need a space on either side of the ==.

Without that it's simply the one-element variant of the condition, which is true when the string is non-empty, as hello==h most definitely is.