Unix Scripting - Finding Minimum and Maximum (Bash Shell)

Question

My code below is part of an assignment, but I'm racking my head against the desk not understanding why it won't assign a "MIN" value. I tried assigning the MIN and MAX to ${LIST[0]} just to have the first index in place, but it returns the whole array, which doesn't make sense to me. I'm executing this on a CentOS VM (which I can't see making a difference). I know the beginning of the first and second "if" statements need better logic, but I'm more concerned on the MIN and MAX outputs.

#!/bin/bash
LIST=()

read -p "Enter a set of numbers. " LIST

MIN=
MAX=

if [ ${#LIST[*]} == 0 ]; then echo "More numbers are needed."; fi

if [ ${#LIST[@]} -gt 0 ]; then
        for i in ${LIST[@]}; do
                if [[ $i -gt $MAX ]]; then
                        MAX=$i
                fi

                if [[ $i -lt $MIN ]]; then
                        MIN=$i
                fi
        done

echo Max is: $MAX.
echo Min is: $MIN.

fi

You need to review what type LIST is? You set it as an empty array and then assign a scalar value using read. You need to include the -a switch to read to maintain LIST as an array — grail
– grail, Commented Jun 14, 2017 at 4:53

agc · Accepted Answer · 2017-06-14 05:15:23Z

1

The code is almost functional.

Since $LIST is an array, not a variable, change read -p "Enter a set of numbers. " LIST to:

read -p "Enter a set of numbers. " -a LIST
Move the $MIN and $MAX init code down 5 lines, (just before the for loop):
```
MIN=
MAX=
```
...and change it to:
```
MIN=${LIST[0]}
MAX=$MIN
```

And it'll work. Test:

echo 3 5 6 | ./minmax.sh

Output:

Max is: 6.
Min is: 3.

answered Jun 14, 2017 at 5:15

agc

8,5342 gold badges33 silver badges53 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Thankless Noodle Over a year ago

I like this solution. I had originally added an OR to my MIN logic (..|| MIN -eq "") and it worked out. What I had failed to remember, being use to other programming languages, is that these were string literals and not integers. It made sense as to why ${LIST[0]} was printing out the whole set up numbers (or single string). Thanks, @agc.

Collectives™ on Stack Overflow

Unix Scripting - Finding Minimum and Maximum (Bash Shell)

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related