AWK: How to decrement values in a column by one

I have a set of values in a column that go

3  
4  
4  
5  
6  
7  
8  
...  

I wish to decrement all these values by 1

Any ideas as开发者_开发问答 to how to formulate this in an AWK script?

thanks

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What if I wish to increment the entries instead of decrementing?

Would awk '{ $7--; print $1 }' work?

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If it's just a single column, this will do:

awk '{ $7--; print $0 }'

Instead of the '7' in '$7' you need to insert your column number; if this number is greater 10, write it as $(77), e.g.

If all columns of a row are affected, use this:

awk '{ for (f=1; f<=NF; f--) $f--
       print $0
      }'

Hope this helps,

Klaus

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If they're in column 4, $4--, and then do whatever else you were going to do (e.g. print).