[unix] Convert decimal to hexadecimal in UNIX shell script

In a UNIX shell script, what can I use to convert decimal numbers into hexadecimal? I thought od would do the trick, but it's not realizing I'm feeding it ASCII representations of numbers.

printf? Gross! Using it for now, but what else is available?

Hexidecimal to decimal:

$ echo $((0xfee10000))
4276158464

Decimal to hexadecimal:

$ printf '%x\n' 26
1a

Tried printf(1)?

printf "%x\n" 34
22

There are probably ways of doing that with builtin functions in all shells but it would be less portable. I've not checked the POSIX sh specs to see whether it has such capabilities.

xd() {
    printf "hex> "
    while read i
    do
        printf "dec  $(( 0x${i} ))\n\nhex> "
    done
}
dx() {
    printf "dec> "
    while read i
    do
        printf 'hex  %x\n\ndec> ' $i
    done
}

Hexidecimal to decimal:

$ echo $((0xfee10000))
4276158464

Decimal to hexadecimal:

$ printf '%x\n' 26
1a

bash-4.2$ printf '%x\n' 4294967295
ffffffff

bash-4.2$ printf -v hex '%x' 4294967295
bash-4.2$ echo $hex
ffffffff

Try:

printf "%X\n" ${MY_NUMBER}

Tried printf(1)?

printf "%x\n" 34
22

There are probably ways of doing that with builtin functions in all shells but it would be less portable. I've not checked the POSIX sh specs to see whether it has such capabilities.

Try:

printf "%X\n" ${MY_NUMBER}

In my case, I stumbled upon one issue with using printf solution:

$ printf "%x" 008 bash: printf: 008: invalid octal number

The easiest way was to use solution with bc, suggested in post higher:

$ bc <<< "obase=16; 008" 8

In zsh you can do this sort of thing:

% typeset -i 16 y
% print $(( [#8] x = 32, y = 32 ))
8#40
% print $x $y
8#40 16#20
% setopt c_bases
% print $y
0x20

Example taken from zsh docs page about Arithmetic Evaluation.

I believe Bash has similar capabilities.

# number conversion.

while `test $ans='y'`
do
    echo "Menu"
    echo "1.Decimal to Hexadecimal"
    echo "2.Decimal to Octal"
    echo "3.Hexadecimal to Binary"
    echo "4.Octal to Binary"
    echo "5.Hexadecimal to  Octal"
    echo "6.Octal to Hexadecimal"
    echo "7.Exit"

    read choice
    case $choice in

        1) echo "Enter the decimal no."
           read n
           hex=`echo "ibase=10;obase=16;$n"|bc`
           echo "The hexadecimal no. is $hex"
           ;;

        2) echo "Enter the decimal no."
           read n
           oct=`echo "ibase=10;obase=8;$n"|bc`
           echo "The octal no. is $oct"
           ;;

        3) echo "Enter the hexadecimal no."
           read n
           binary=`echo "ibase=16;obase=2;$n"|bc`
           echo "The binary no. is $binary"
           ;;

        4) echo "Enter the octal no."
           read n
           binary=`echo "ibase=8;obase=2;$n"|bc`
           echo "The binary no. is $binary"
           ;;

        5) echo "Enter the hexadecimal no."
           read n
           oct=`echo "ibase=16;obase=8;$n"|bc`
           echo "The octal no. is $oct"
           ;;

        6) echo "Enter the octal no."
           read n
           hex=`echo "ibase=8;obase=16;$n"|bc`
           echo "The hexadecimal no. is $hex"
           ;;

        7) exit 
        ;;
        *) echo "invalid no." 
        ;;

    esac
done

In zsh you can do this sort of thing:

% typeset -i 16 y
% print $(( [#8] x = 32, y = 32 ))
8#40
% print $x $y
8#40 16#20
% setopt c_bases
% print $y
0x20

Example taken from zsh docs page about Arithmetic Evaluation.

I believe Bash has similar capabilities.

This is not a shell script, but it is the cli tool I'm using to convert numbers among bin/oct/dec/hex:

    #!/usr/bin/perl

    if (@ARGV < 2) {
      printf("Convert numbers among bin/oct/dec/hex\n");
      printf("\nUsage: base b/o/d/x num num2 ... \n");
      exit;
    }

    for ($i=1; $i<@ARGV; $i++) {
      if ($ARGV[0] eq "b") {
                    $num = oct("0b$ARGV[$i]");
      } elsif ($ARGV[0] eq "o") {
                    $num = oct($ARGV[$i]);
      } elsif ($ARGV[0] eq "d") {
                    $num = $ARGV[$i];
      } elsif ($ARGV[0] eq "h") {
                    $num = hex($ARGV[$i]);
      } else {
                    printf("Usage: base b/o/d/x num num2 ... \n");
                    exit;
      }
      printf("0x%x = 0d%d = 0%o = 0b%b\n", $num, $num, $num, $num);
    }

In zsh you can do this sort of thing:

% typeset -i 16 y
% print $(( [#8] x = 32, y = 32 ))
8#40
% print $x $y
8#40 16#20
% setopt c_bases
% print $y
0x20

Example taken from zsh docs page about Arithmetic Evaluation.

I believe Bash has similar capabilities.

Sorry my fault, try this...

#!/bin/bash
:

declare -r HEX_DIGITS="0123456789ABCDEF"

dec_value=$1
hex_value=""

until [ $dec_value == 0 ]; do

    rem_value=$((dec_value % 16))
    dec_value=$((dec_value / 16))

    hex_digit=${HEX_DIGITS:$rem_value:1}

    hex_value="${hex_digit}${hex_value}"

done

echo -e "${hex_value}"

Example:

$ ./dtoh 1024
400

In my case, I stumbled upon one issue with using printf solution:

$ printf "%x" 008 bash: printf: 008: invalid octal number

The easiest way was to use solution with bc, suggested in post higher:

$ bc <<< "obase=16; 008" 8

xd() {
    printf "hex> "
    while read i
    do
        printf "dec  $(( 0x${i} ))\n\nhex> "
    done
}
dx() {
    printf "dec> "
    while read i
    do
        printf 'hex  %x\n\ndec> ' $i
    done
}

Tried printf(1)?

printf "%x\n" 34
22

There are probably ways of doing that with builtin functions in all shells but it would be less portable. I've not checked the POSIX sh specs to see whether it has such capabilities.

This is not a shell script, but it is the cli tool I'm using to convert numbers among bin/oct/dec/hex:

    #!/usr/bin/perl

    if (@ARGV < 2) {
      printf("Convert numbers among bin/oct/dec/hex\n");
      printf("\nUsage: base b/o/d/x num num2 ... \n");
      exit;
    }

    for ($i=1; $i<@ARGV; $i++) {
      if ($ARGV[0] eq "b") {
                    $num = oct("0b$ARGV[$i]");
      } elsif ($ARGV[0] eq "o") {
                    $num = oct($ARGV[$i]);
      } elsif ($ARGV[0] eq "d") {
                    $num = $ARGV[$i];
      } elsif ($ARGV[0] eq "h") {
                    $num = hex($ARGV[$i]);
      } else {
                    printf("Usage: base b/o/d/x num num2 ... \n");
                    exit;
      }
      printf("0x%x = 0d%d = 0%o = 0b%b\n", $num, $num, $num, $num);
    }

Sorry my fault, try this...

#!/bin/bash
:

declare -r HEX_DIGITS="0123456789ABCDEF"

dec_value=$1
hex_value=""

until [ $dec_value == 0 ]; do

    rem_value=$((dec_value % 16))
    dec_value=$((dec_value / 16))

    hex_digit=${HEX_DIGITS:$rem_value:1}

    hex_value="${hex_digit}${hex_value}"

done

echo -e "${hex_value}"

Example:

$ ./dtoh 1024
400

Try:

printf "%X\n" ${MY_NUMBER}

In zsh you can do this sort of thing:

% typeset -i 16 y
% print $(( [#8] x = 32, y = 32 ))
8#40
% print $x $y
8#40 16#20
% setopt c_bases
% print $y
0x20

Example taken from zsh docs page about Arithmetic Evaluation.

I believe Bash has similar capabilities.

Try:

printf "%X\n" ${MY_NUMBER}

# number conversion.

while `test $ans='y'`
do
    echo "Menu"
    echo "1.Decimal to Hexadecimal"
    echo "2.Decimal to Octal"
    echo "3.Hexadecimal to Binary"
    echo "4.Octal to Binary"
    echo "5.Hexadecimal to  Octal"
    echo "6.Octal to Hexadecimal"
    echo "7.Exit"

    read choice
    case $choice in

        1) echo "Enter the decimal no."
           read n
           hex=`echo "ibase=10;obase=16;$n"|bc`
           echo "The hexadecimal no. is $hex"
           ;;

        2) echo "Enter the decimal no."
           read n
           oct=`echo "ibase=10;obase=8;$n"|bc`
           echo "The octal no. is $oct"
           ;;

        3) echo "Enter the hexadecimal no."
           read n
           binary=`echo "ibase=16;obase=2;$n"|bc`
           echo "The binary no. is $binary"
           ;;

        4) echo "Enter the octal no."
           read n
           binary=`echo "ibase=8;obase=2;$n"|bc`
           echo "The binary no. is $binary"
           ;;

        5) echo "Enter the hexadecimal no."
           read n
           oct=`echo "ibase=16;obase=8;$n"|bc`
           echo "The octal no. is $oct"
           ;;

        6) echo "Enter the octal no."
           read n
           hex=`echo "ibase=8;obase=16;$n"|bc`
           echo "The hexadecimal no. is $hex"
           ;;

        7) exit 
        ;;
        *) echo "invalid no." 
        ;;

    esac
done