CODEWITHSUNDEEP
arraysbashshellbyte
alecrosic
alecrosic

Reputation: 689

How to convert a string into hexadecimal in Bash

I've found many posts on StackOverflow which have covered this question in C++, C# and other languages, but none with Shell.

Using Bash/Shell, how do I convert a random String into a byte array?

I tried:

echo "some string" | xxd -r -p

but it didn't work.

I basically want a byte output - e.g. )?e?GV??vY?Ge?#G

Upvotes: 17

Views: 30000

Answers (2)

user2350426
user2350426

Reputation:

If you want to get the hex values of some string, then this works:

$ echo "testing some values"$'\157' | xxd
0000000: 7465 7374 696e 6720 736f 6d65 2076 616c  testing some val
0000010: 7565 736f 0a                             ueso.

If you just need the "plain" string:

$ echo "testing some values"$'\157' | xxd -p
74657374696e6720736f6d652076616c7565736f0a

If you need to "reverse" an hex string, you do:

$ echo "74657374696e6720736f6d652076616c7565736f0a" | xxd -r -p
testing some valueso

If what you need is the character representation (not hex), you could do:

$ echo "testing:"$'\001\011\n\bend test'  | od -vAn -tcx1
  t   e   s   t   i   n   g   : 001  \t  \n  \b   e   n   d    
 74  65  73  74  69  6e  67  3a  01  09  0a  08  65  6e  64  20
  t   e   s   t  \n
 74  65  73  74  0a

Or:

$ echo "testing:"$'\001\011\n\bend test'  | od -vAn -tax1
  t   e   s   t   i   n   g   : soh  ht  nl  bs   e   n   d  sp
 74  65  73  74  69  6e  67  3a  01  09  0a  08  65  6e  64  20
  t   e   s   t  nl
 74  65  73  74  0a

Upvotes: 33

Eugene
Eugene

Reputation: 7258

Looks like you want to convert hex string to bytes. xxd needs a starting point (since it is used to patch binary files and such)

string="626c610a"
echo "0: $string" | xxd -r

xxd will also silently skip any invalid hex, so check your data if you get empty output.

Upvotes: 0

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