Ascii/Hex convert in bash

Question

I\'m now doing it this way:

[root@~]# echo Aa|hexdump -v
0000000 6141 000a                              
0000003
[root@~]# echo -e \"\\x41\\x41\\x41\\x41\"
A         


        

Answer 1

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.

Answer 2

$> printf "%x%x\n" "'A" "'a"
4161

Answer 3

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

Answer 4

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

Answer 5

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 :)

Answer 6

echo -n Aa | hexdump -e '/1 "%02x"'; echo