Optical Dump

Problem

Ever need to look at a file, but have not been able to – due to hidden control characters, etc.



Solution

Or just needed to see spaces and end of line characters, comparing files, etc. Optical dump or more specifically the od command, can be extremely useful for display ascii characters. See the example.



Example


The basic syntax looks like this:

od -c filename
Heres a demo:
echo "hi
> world
> " | od -c
0000000 h i n w o r l d n n
0000012

Also useful if wanted to look at a binary file, without breaking your terminal. 🙂 Or looking through encryption.

Also an easy converting of ascii to hex:
dd if=/dev/urandom count=1 bs=128 | od -x
1+0 records in
1+0 records out
0000000 5715 4ac5 e457 9c7b 013b 94f8 cdb7 36b7
0000020 1ae0 a650 e236 c4e3 589f 4af2 dddd f67c
0000040 f722 58b3 7e4e 1de4 6de4 36fb 2c8a 6864
0000060 c682 f951 f966 108f b9dd eaca aefd 8a8a
0000100 da45 7e0f a3ae 350f b0b8 a1f8 1dbe aa4c
0000120 aad8 7002 f0ec 2a94 076a 70f9 0d6f cf44
0000140 1cb2 88b6 9db2 258c 6b4e 08f7 bc41 e6e2
0000160 5ec1 101a f849 b50c 322a 43cf 1520 7dba
0000200



Reference

[tags]optical dump, binary format, Unix Coding School[/tags]



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