Bash Format HEX string

Question

Anyone know a standard unix command to format a running SHA1 hex string like this:

344F9DA1EA1859437077CCA38923C67797BDB8F6

into this:

344F9DA1 EA185943 7077CCA3 8923C677 97BDB8F6

Like:

echo "344F9DA1EA1859437077CCA38923C67797BDB8F6" | awk ...

Martin · Accepted Answer · 2011-03-14 22:15:39Z

5

Here's one option with sed:

echo "344F9DA1EA1859437077CCA38923C67797BDB8F6" | sed -E 's/.{8}/& /g'

(replace any sequence of 8 characters by itself plus one space)

edited Mar 14, 2011 at 22:15

answered Mar 14, 2011 at 21:59

Martin

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7 Comments

Hugo Sereno Ferreira Over a year ago

Nice. But I forgot to mention I'm on OSX, and SED doesn't seem to have a -r flag. Any tips?

shellter Over a year ago

You probably don't need the -r, but points for a shorter command to Martin!

Martin Over a year ago

Changed it to sed -E 's/[0-9A-F]{8}/& /g' which seems to work on both OSX and my Linux box

ninjalj Over a year ago

@Hugo: Just add lots of backslashes for things that don't work. Also, & is the traditional way to refer to the whole match. Maybe something similar to s/[0-9A-F]\{8\}/& /g ? No OSX here.

William Pursell Over a year ago

-r is non-standard. For portability, you can do: sed -e 's/$.\{8\}$/\1 /g'

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Ezra · Accepted Answer · 2011-03-14 22:06:17Z

4

To add a space after every eighth character, try:

If the contents are on a single line in a file named FILENAME:

sed 's/.\{8\}/& /g' FILENAME

Or, if they're split across multiple lines. Again, for a file named FILENAME:

sed ':a;$!{N;s/\n//;ba;};s/.\{8\}/& /g' FILENAME

To illustrate the difference:

ezra@ubuntu:~$ cat test.file
344F9DA1EA1859437077CCA38923C67797BDB8F6
344F9DA1EA1859437077

ezra@ubuntu:~$ sed ':a;$!{N;s/\n//;ba;};s/.\{8\}/& /g' test.file
344F9DA1 EA185943 7077CCA3 8923C677 97BDB8F6 344F9DA1 EA185943 7077

ezra@ubuntu:~$ sed 's/.\{8\}/& /g' test.file
344F9DA1 EA185943 7077CCA3 8923C677 97BDB8F6
344F9DA1 EA185943 7077

answered Mar 14, 2011 at 22:06

Ezra

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Comments

ataylor · Accepted Answer · 2011-03-14 22:08:08Z

3

You can do this in bash without piping at all.

bash$ FOO="344F9DA1EA1859437077CCA38923C67797BDB8F6"
bash$ echo ${FOO:0:8} ${FOO:8:8} ${FOO:16:8} ${FOO:24:8} ${FOO:32:8}
344F9DA1 EA185943 7077CCA3 8923C677 97BDB8F6

answered Mar 14, 2011 at 22:08

ataylor

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1 Comment

Peter.O Over a year ago

good - and with no trailing space ...also: eval echo \${FOO:{0..4}*8:8}

ninjalj · Accepted Answer · 2011-03-14 22:14:09Z

2

Another one:

echo "344F9DA1EA1859437077CCA38923C67797BDB8F6" | fold -b8 | tr "\n" " "

answered Mar 14, 2011 at 22:14

ninjalj

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Comments

shellter · Accepted Answer · 2011-03-14 22:03:08Z

1

How about

echo "344F9DA1EA1859437077CCA38923C67797BDB8F6" \
| awk '{
    printf("%s %s %s %s %s\n", 
      substr($0,1,8),  substr($0,9,8), substr($0,17,8), substr($0,25,8),
      substr($0,33,8), substr($0,41,8)    )
    }
 '

I hope this helps.

answered Mar 14, 2011 at 22:03

shellter

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1 Comment

ninjalj Over a year ago

Don't know about OSX 's awk, but in GNU awk: echo "344F9DA1EA1859437077CCA38923C67797BDB8F6" | awk --posix '{gsub("([0-9A-F]){8}","& ");print}'.

Dennis Williamson · Accepted Answer · 2011-03-14 22:45:02Z

1

Using pure Bash (version 3.2 or greater):

hex=344F9DA1EA1859437077CCA38923C67797BD
p='(.{8})'; unset patt; for i in {1..5}; do patt+=$p; done
[[ $hex =~ $patt ]]
string=${BASH_REMATCH[@]:1}
echo "$string"    # output: 344F9DA1 EA185943 7077CCA3 8923C677 97BDB8F6

answered Mar 14, 2011 at 22:45

Dennis Williamson

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