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Old 07-30-2007, 08:38 PM   #1
petcherd
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N00b's bash, sed, or awk question


I'm trying to compare two huge directory trees that start like this:

/backup/volume/20070718/tree/...

and

/backup/volume/20070719/tree/...

diff doesn't work for me because it sees that difference in the dates, and considers every line different.

How can I trim-off the first 28 characters of each line of a text file?

I had considered using sed to substitute "/backup/volume/20070718/tree/" with "/", but I got messed-up with the / characters.
 
Old 07-30-2007, 08:51 PM   #2
wjevans_7d1@yahoo.co
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Code:
sed -e 's/^............................//' input_file > output_file
#          1234567890123456789012345678
#                   1111111111222222222
If you're sure you don't want the first 28 characters, this will get rid of 'em no matter what they are. The only hitch is that any line which contains fewer than 28 characters will be left alone.

Hope this helps.
 
Old 07-30-2007, 11:43 PM   #3
petcherd
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No, that's perfect for me! I am certain that I have no lines shorter than 28 characters. I'm going to run back to my server's shell and give it a try right now....

It works just right.

Last edited by petcherd; 07-31-2007 at 12:11 AM.
 
Old 07-31-2007, 01:09 AM   #4
jlliagre
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Quote:
Originally Posted by petcherd
I had considered using sed to substitute "/backup/volume/20070718/tree/" with "/", but I got messed-up with the / characters.
Here is one way to overcome the / issue with sed:
Code:
sed 's"/backup/volume/20070719/tree/""'
 
Old 07-31-2007, 03:44 AM   #5
mRgOBLIN
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Code:
sed 's/^.\{,28\}//'
that will remove the first 28 characters for you
 
Old 08-01-2007, 07:42 AM   #6
wjevans_7d1@yahoo.co
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For some versions of sed, this will give you a syntax error:

Code:
sed 's/^.\{,28\}//'
If that happens, be more explicit:

Code:
sed 's/^.\{0,28\}//'
 
  


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