bash ascii to hex

Question

was wondering if anyone could help me with converting ascii to hex in bash. Example code:

#!/bin/bash 
STR = "hello"
#Convert to hex
HEXVAL = $STR #(in hex here?)

I want hexval to have the value: 68656C6C6F (hello in hex)

Answer 1

$ str="hello"
$ hex=$(xxd -pu <<< "$str")
$ echo "$hex"
6C6C6568A6F

Or:

$ hex=$(hexdump -e '"%X"' <<< "$str")
$ echo "$hex"
6C6C6568A6F

Careful with the '"%X"'; it has both single quotes and double quotes.

Answer 2

You have several options

$ printf hello | xxd
0000000: 6865 6c6c 6f                             hello

See also: Ascii/Hex convert in bash

Answer 3

Pure BASH convertor of string to printable hexadecimal sequence and back

str2hex_echo() {
    # USAGE: hex_repr=$(str2hex_echo "ABC")
    #        returns "0x410x420x43"
    local str=${1:-""}
    local fmt="0x%x"
    local chr
    local -i i
    for i in `seq 0 $((${#str}-1))`; do
        chr=${str:i:1}
        printf  "${fmt}" "'${chr}"
    done
}

hex2str_echo() {
    # USAGE: ASCII_repr=$(hex2str_echo "0x410x420x43")
    #        returns "ABC"
    echo -en "'${1:-""//0x/\\x}'"
}

EXPLANATION

ASCII->hex: The secret sauce of efficient conversion from character to its underlying ASCII code is feature in printf that, with non-string format specifiers, takes leading character being a single or double quotation mark as an order to produce the underlying ASCII code of the next symbol. This behavior is documented in GNU BASH reference, but is also exposed in details together with many other other wonderful utilities in Greg's (also known as GreyCat's) wiki page BashFAQ/071 dedicated to char-ASCII conversions.

Answer 4

here's a one liner (a little complex but works fine):

#!/bin/bash

echo '0x'"`echo $1 | hexdump -vC |  awk 'BEGIN {IFS="\t"} {$1=""; print }' | awk '{sub(/\|.*/,"")}1'  | tr -d '\n' | tr -d ' '`" | rev | cut -c 3- | rev

Answer 5

xxd -p -u <<< "$STR" | sed 's/\(..\)/0x&, /g; s/, $//;'

0x68, 0x65, 0x6C, 0x6C, 0x6F, 0x0A