Question

3

Why does my condition always evaluate as true?

rated 0 times [ 3] [ 0] / answers: 1 / hits: 4091 / 3 Years ago, fri, july 9, 2021, 6:11:29

I'm writing my first bash script and I've hit a snag. Here's an example where I ask for a name, ask for an age, and display a message that changes depending on whether or not the age is <= 35:

#!/bin/bash

ageLimit = 34

echo "What is your name?"

read userName

echo "How old are you?"

read userAge

if (( "$userAge" -le "$ageLimit" )); then

    echo "Hey, $userName.  At $userAge years old, you are young."

else

    echo "Gosh, $userName.  At $userAge years old, you're pretty old."

fi

No matter what number I answer for age, I am told I am young. This is running on Raspbian -- in case that helps. Thanks!

Jeremy

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tubequ

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3 Years ago

answered 3 Years ago olltea · Accepted Answer

Whitespaces make a lot of difference in whell script, you need to take care of them. There is no space between the variable name and the = sign and its value.

Rewrite your shell script as follows:

#!/bin/bash

ageLimit=34

echo "What is your name?"

read userName

echo "How old are you?"

read userAge

if [[ "$userAge" -le "$ageLimit" ]]; then

    echo "Hey, $userName.  At $userAge years old, you are young."

else

   echo "Gosh, $userName.  At $userAge years old, you're pretty old."

fi

Refer to a good tutorial on shell scripting while you make your hands dirty. One good tutorial googling returns is this:

Linux Shell Scripting Tutorial v1.05r3
A Beginner's handbook by Vivek G. Gite

You may also want to know this:

Difference between single and double square brackets in bash