Question

I wrote the following script in Bash but it is not printing the desired output:

a="abc"

if (test "$a"="$a ") then 
    echo "true "
else
    echo "false "
fi

This script should print false but it isn’t. I’m new to Bash scripting, so can anyone please tell me why it is not printing false?

Answer 1

You’re giving test only one argument: "$a"="$a ", which is equivalent to "$a=$a ". When test gets only one argument, it evaluates to 0/true/success if that argument contains at least one character, and to 1/false/error otherwise. The minimal fix would be to put spaces around the =, so you’re giving it three separate arguments:

if (test "$a" = "$a ") then

but I’d really recommend writing it in a Bashier style:

if [[ "$a" = "$a " ]] then

(Note that the ( and ) in the original version merely cause test to be run in a subshell, which really serves no purpose at all.)