Shell Programming and Scripting

Thanks Don Cragun,

I should know better than try and post code without testing, someone here is certain to keep me honest!

I think the spirit of this is if you find yourself with large numbers of logic transformations a consider using a data table, and if you find yourself defining large data tables consider...a data file.

I don't know what the OPs transformation here was but lets say its a tax update for 2008-2009 you could save the program (with Don Cragun's fixes) as tax_update_2008-2009.awk any you would have an antonymous fix script.

However we could also write a tax_update.awk program and a 2008-2009.dat data file. Then when it comes time to do 2009-2010 updates and new .dat file is all that's needed:

Code:

$ head -4 2008-2009.dat 
236 199  32 200
236  32 199 200
236 218  32 200
236 237  32 200

$ cat tax_update.awk
FILENAME ~ "[.]dat$" { B[$1,$2,$3]=$4; next }
{ A[++c]=$1 }
END {
 for(i=1;i<=c;i++) {
        if((A[i] SUBSEP A[i+1] SUBSEP A[i-1]) in B) A[i]=B[A[i],A[i+1],A[i-1]]
        print A[i]
 }
}

$ awk -f tax_update.awk 2008-2009.dat taxfile > taxfile_fixed