Shell scripting: functions

Question

I can't get my function to do what I want. When I call my function get_from_A_to_F I give it an argument $remainder. I want my function to substitute a number higher than 9 to a specific letter. If the argument is equal to 10 than it should change it to "A". However it still leaves it as a 10. What am I doing wrong here?

#!/bin/sh

get_from_A_to_F() 
{
    case $1 in
        10) $1="A"
        ;;
        11) $1="B"
        ;;
        12) $1="C"
        ;;
        13) $1="D"
        ;;
        14) $1="E"
        ;;
        15) $1="F"     
        ;; 
        [0-9]) $1=$1
        ;;  
    esac
    echo $1
}

read number
string=""
index=`expr index $number "."`
if [ $index -eq 0 ]
then
    integer=$number
    fraction=0
else
    integer=`expr substr $number 1 $(expr $index - 1)`
    fraction=`expr "$number - $integer" | bc`
fi
result=$integer
while [ $result -ne 0 ] 
do
    remainder=`expr $result % 16`
    get_from_A_to_F $remainder
    result=`expr $result / 16`
    string=$remainder$string
done

Current output(if number read is 634):

634
test: 43: 10=A: not found
10
test: 43: 7=7: not found
7
test: 43: 2=2: not found
2

Tried it, still doesn't work. Does anyone have any other ideas? — Linas
– Linas, Commented Nov 2, 2012 at 17:27
turn on your shell debugging feature, set -x will show cmds with substituted variable values. set -vx shows current command or block (can be confusing at first) + the substituted variable values. Put one of those just at the top of your function, and you can turn the same off with set +x OR set +vx. Then you'll be able to see what is happening inside your script. (try eval again, either I don't understand what you're trying to achieve, or something is wonky). Also please edit you Q to include sample usage with expected output and current output. Good luck. — shellter
– shellter, Commented Nov 2, 2012 at 17:50
If the number read is 634 the output of my script is: 634 test: 43: 10=A: not found 10 test: 43: 7=7: not found 7 test: 43: 2=2: not found 2 — Linas
– Linas, Commented Nov 2, 2012 at 17:57
sorry, impossible to read this as a comment. Please edit your question with this info. Good luck. — shellter
– shellter, Commented Nov 2, 2012 at 18:20

glenn jackman · Accepted Answer · 2012-11-02 20:38:32Z

1

To assign to $1, you do: set -- value

get_from_A_to_F is not a great function name for converting to hex. Try this:

to_hex() { printf "%X\n" "$1"; }

read number

regex1='^[+-]?[0-9]+(\.[0-9]*)?$'
regex2='^[+-]?[0-9]*\.[0-9]+$'
if ! [[ $number =~ $regex1 || $number =~ $regex2 ]]; then
    echo "doesn't look like a number: $number"
else
    integer=${number%.*}
    fraction=${number#*.}
    (( integer == fraction )) && fraction=0   # no decimal point
    hex=$(to_hex $integer)
    # you don't use $fraction anywhere?
fi

answered Nov 2, 2012 at 20:38

glenn jackman

249k42 gold badges233 silver badges362 bronze badges

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

Collectives™ on Stack Overflow

Shell scripting: functions

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related