I'm now doing it this way:
[root@~]# echo Aa|hexdump -v 0000000 6141 000a 0000003 [root@~]# echo -e "\x41\x41\x41\x41" AAAA But it's not exactly behaving as I wanted,
the hex form of Aa should be 4161,but the output is 6141 000a,which seems not making sense.
and when performing hex to ascii,is there another utility so that I don't need the prefix \x ?
The reason is because hexdump by default prints out 16-bit integers, not bytes. If your system has them, hd (or hexdump -C) or xxd will provide less surprising outputs - if not, od -t x1 is a POSIX-standard way to get byte-by-byte hex output. You can use od -t x1c to show both the byte hex values and the corresponding letters.
If you have xxd (which ships with vim), you can use xxd -r to convert back from hex (from the same format xxd produces). If you just have plain hex (just the '4161', which is produced by xxd -p) you can use xxd -r -p to convert back.
xxd -p -r AAA,this doesn't work,can it retrieve parameters from command line directly?
echo 4161 | xxd -r -p' or 'echo Aa | xxd -p'
xxd is broken as of now. It desplays all zeroes instead of data. Maybe specific to my setup (xxd 2021-10-22, Ubuntu 22.04, large files > 2Gb), but anyway you should be aware of that (I lost some time to figure out what's going on).
xxd would add zero hex data to a file that wasn't already zeroed.For the first part, try
echo Aa | od -t x1 It prints byte-by-byte
$ echo Aa | od -t x1 0000000 41 61 0a 0000003 The 0a is the implicit newline that echo produces.
Use echo -n or printf instead.
$ printf Aa | od -t x1 0000000 41 61 0000002 
$> printf "%x%x\n" "'A" "'a" 4161 
printf solution here should be the accepted answer. It is the most portable and the most simple, and keeps with POSIX compliance without needing external tools that may or may not be available.
For single line solution:
echo "Hello World" | xxd -ps -c 200 | tr -d '\n' It will print:
48656c6c6f20576f726c640a or for files:
cat /path/to/file | xxd -ps -c 200 | tr -d '\n' For reverse operation:
echo '48656c6c6f20576f726c640a' | xxd -ps -r It will print:
Hello World With bash :
a=abcdefghij for ((i=0;i<${#a};i++));do printf %02X \'${a:$i:1};done 6162636465666768696A
I use:
> echo Aa | tr -d '\n' | xxd -p 4161 > echo 414161 | tr -d '\n' | xxd -r -p AAa The tr -d '\n' will trim any possible newlines in your input
I don't know how it crazy it looks but it does the job really well
ascii2hex(){ a="$@";s=0000000;printf "$a" | hexdump | grep "^$s"| sed s/' '//g| sed s/^$s//;} Created this when I was trying to see my name in HEX ;) use how can you use it :)
Text2Conv="Aa" for letter in $(echo "$Text2Conv" | sed "s/\(.\)/'\1 /g");do printf '%x' "$letter";done 4161
The trick is using sed to parse the Text2Conv to format we can then seperate anf loop using for.
Finally got the correct thing
echo "Hello, world!" | tr -d '\n' | xxd -ps -c 200 
echo -n "Hello, world!" | xxd -ps -c 200 would also work
xxd -ps -c 200 <<< "Hello, world!"here a little script I wrote to convert ascii to hex. hope it helps:
echo '0x'"`echo 'ASCII INPUT GOES HERE' | hexdump -vC | awk 'BEGIN {IFS="\t"} {$1=""; print }' | awk '{sub(/\|.*/,"")}1' | tr -d '\n' | tr -d ' '`" | rev | cut -c 3- | rev SteinAir's answer above was helpful to me -- thank you! And below is a way it inspired, to convert hex strings to ascii:
for h in $(echo "4161" | sed "s/\(..\)/\1 /g"); do printf `echo "\x$h"`;done Aa 
echo -n Aa | hexdump -e '/1 "%02x"'; echo Very quick and short:
string='Hello World.' oIFS="$IFS" IFS=$'\n' printf '%02X\n' ${string//?/$'\n'\'&}; IFS="$oIFS" Will produce:
48 65 6C 6C 6F 20 57 6F 72 6C 64 2E Yes, in order to handle space, we have to play with $IFS.
string='Hello World.' oIFS="$IFS" IFS=$'\n' printf -v string '%02X\n' ${string//?/$'\n'\'&}; IFS="$oIFS" mapfile -t array <<<${string%$'\n'} echo ${array[@]@Q} '48' '65' '6C' '6C' '6F' '20' '57' '6F' '72' '6C' '64' '2E' In a function, we could localize $IFS, things become a little simplier.
ascii2hex() { local _varname=$1 _string=${*:2} IFS=$'\n' printf -v _string '%02X\n' ${_string//?/$'\n'\'&} mapfile -t "$_varname" <<<${_string%$'\n'} } ascii2hex myArray 'Hello world!' echo ${myArray[@]@Q} '48' '65' '6C' '6C' '6F' '20' '77' '6F' '72' '6C' '64' '21' Note: as function use ${*:2} as source string, space don't need to be quoted:
ascii2hex myArray Hello world! echo ${myArray[@]@Q} '48' '65' '6C' '6C' '6F' '20' '77' '6F' '72' '6C' '64' '21' Simply:
printf '%b' ${myArray[@]/#/\\x} Hello world! printf -v string '%b' ${myArray[@]/#/\\x} echo $string Hello world! hex2ascii() { local _array=(${*:2}) printf -v "$1" '%b' ${_array[@]/#/\\x} } hex2ascii mystring ${myArray[@]} echo "$mystring" Hello world! 
according to http://mylinuxbook.com/hexdump/ you might use the hexdump format parameter
echo Aa | hexdump -C -e '/1 "%02X"' will return 4161
to add an extra linefeed at the end, append another formatter.
BUT: the format given above will give multiplier outputs for repetitive characters
$ printf "Hello" | hexdump -e '/1 "%02X"' 48656C* 6F instead of
48656c6c6f 
jcomeau@aspire:~$ echo -n The quick brown fox jumps over the lazy dog | python -c "print raw_input().encode('hex')," 54686520717569636b2062726f776e20666f78206a756d7073206f76657220746865206c617a7920646f67 jcomeau@aspire:~$ echo -n The quick brown fox jumps over the lazy dog | python -c "print raw_input().encode('hex')," | python -c "print raw_input().decode('hex')," The quick brown fox jumps over the lazy dog it could be done with Python3 as well, but differently, and I'm a lazy dog.
python != bash
sed, hexdump, printf, awk, or xxd.echo -en 'hello\nyou\nthere' | sed -z "s/\(.\)/'\1\x0/g" | xargs -0 printf '%02x' 68656c6c6f0a796f750a7468657265 echo '68656c6c6f0a796f750a7468657265' | sed 's/\(..\)/\\\\x\1/g' | xargs printf hello you there echo append a carriage return at the end.
Use
echo -e to remove the extra 0x0A
Also, hexdump does not work byte-per-byte as default. This is why it shows you bytes in a weird endianess and why it shows you an extra 0x00.
