Bash shell Decimal to Binary base 2 conversion

Question

I\'m looking for an easy way in Bash to convert a decimal number into a binary number. I have variables that need to be converted:

$ip1 $ip2 $ip3 $ip4
         


        

Answer 1

Decimal to Binary using only Bash

Any integer number can be converted ti binary using it::

touch dec2bin.bash && chmod +x "$_" && vim "$_"

And, then copy paste the following:

#!/bin/bash
num=$1;
dec2bin()
{
    op=2; ## Since we're converting to binary
    quo=$(( $num/ $op)); ## quotient
    rem=$(( $num% $op)); ## remainder
    array=(); ## array for putting remainder inside array
    array+=("$rem"); ## array expansion
        until [[ $quo -eq 0 ]]; do
            num=$quo; ## looping to get all remainder, untill the remainder is 0
            quo=$(( $num / $op));
            rem=$(( $num % $op));
            array+="$rem"; ## array expansion
        done
    binary=$(echo "${array[@]}" | rev); ## reversing array
    printf "$binary\n"; ## print array
}
main()
{
[[ -n ${num//[0-9]/} ]] &&
    { printf "$num is not an integer bruv!\n"; return 1;
    } || { dec2bin $num; }
}
main;

For example:

./dec2bin.bash $var
110100100

Integer must be added!!

./dec2bin.bash 420.py
420.py is not an integer bruv!

Also, another way using python: Much slower

python -c "print(bin(420))"
0b110100100

Hexadecimal to Binary using only Bash

Similarly, hexadecimal to binary, as follows using only bash:

#!/usr/local/bin/bash ## For Darwin :( higher bash :)
#!/bin/bash ## Linux :)
hex=$1;
hex2bin()
{
    op=2; num=$((16#$hex));
    quo=$(( $num/ $op));
    rem=$(( $num% $op));
    array=();
    array+=("$rem");
        until [[ $quo -eq 0 ]]; do
            num=$quo;
            quo=$(( $num / $op));
            rem=$(( $num % $op));
            array+="$rem";
        done
    binary=$(echo "${array[@]}" | rev);
    printf "Binary of $1 is: $binary\n";
}
main()
{
[[ -n ${hex//[0-9,A-F,a-f]/} ]] &&
    { printf "$hex is not a hexa decimal number bruv!\n"; return 1;
    } || { hex2bin $hex; }
}
main;

For example:

./hex2bin.bash 1aF
Binary of 1aF is: 110101111

Hex must be passed:

./hex2bin.bash XyZ
XyZ is not a hexa decimal number bruv!