[SOLVED] Simple condition getting wrong evaluation result in bash

Issue

I have this bash script getting a Boolean parameter, based on the answer here
I created this simple condition, for some reason I am getting false results

#!/bin/bash

copyFile() {
    echo "copyFile #Parameter:$1"

    if [ "$1" ]; then
             echo "Parameter is true"
        else
             echo "Parameter is false"
        fi
}



copyFile true
copyFile false

execution result:

[admin@local_ip_tmp]$ ./test.sh
copyFile #Parameter:true
Parameter is true
copyFile #Parameter:false
Parameter is true

The last result should have "Parameter is false" I am not sure what is going on.
What am doing wrong?

Solution

The accepted answer on the linked post starts with:

bash doesn't know boolean variables, nor does test

So, as stated in the comments^[1][2] if [ "$1" ]; is evaluated to if [ -n "$1" ], and since $1 isn't empty, "Parameter is true" will be printed.

---

To test if the string "true" is given, you can use the following code

#!/bin/bash

copyFile() {
    echo "copyFile #Parameter:$1"

    if [ "$1" = "true" ]; then
    echo "Parameter is true"
    else
        echo "Parameter is false"
    fi
}

copyFile "true"
copyFile "false"

This will produce:

copyFile #Parameter:true
Parameter is true
copyFile #Parameter:false
Parameter is false

as you can test on this online demo.

Answered By - 0stone0