Convert signed int number to unsigned whith shell script

Question

I need to convert signed int32 number to unsigned using shell script

for example :

convert  Input : -256
Expected output: 4294967040

I tried something like this for negative numbers: SIGNED=-256 UNSIGNED=$((0x`printf '%x' $SIGNED | grep -Eo '.{8}$'`)) — Songe, Sep 21 '16 at 07:52

score 5 · Accepted Answer · answered Sep 21 '16 at 07:38

5

this can help you;

#!/bin/bash
input=$1
if [[ $input -lt "0" ]]; then
    output=$((4294967296+$input))
else
    output=$input
fi
echo $output


#signed int32;
#–2,147,483,648 to 2,147,483,647
#unsigned int32
#0 to 4,294,967,295

answered Sep 21 '16 at 07:38

Mustafa DOGRU

3,994
1
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score 3 · Answer 2 · answered Mar 20 '17 at 21:16

Here goes, probably not the quickest, but seems to work

unsigned_to_signed()
{
    local hex=$(printf "0x%x" $(( $* )))
    local unsigned=$(printf "%u" $hex )
    echo $unsigned
}

unsigned_to_signed32()
{
    local hex=$(printf "0x%x" $(( $* & 0xFFFFFFFF )))
    local unsigned=$(printf "%u" $hex )
    echo $unsigned
}

unsigned_to_signed -256
18446744073709551360

unsigned_to_signed32 -256
4294967040

Convert signed int number to unsigned whith shell script

2 Answers2