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Top Forums Shell Programming and Scripting awk updating one file with another, comparing, updating Post 302203614 by mecano on Monday 9th of June 2008 11:07:29 AM
Old 06-09-2008
oh my.... Smilie

thanks a lot !

I thought the solution was something like store keys from file1, iterate them on file2, then reverse the iteration to find missing records... I was far far away from the beauty of awk...

if I understand correctly, awk reads the two files and automagically merged records itself ? It means that there is no need to store values from file1 to compare them to file2 ? Beautifull...

Two things I don't get: the use of the underscore (while i guess it stands for "all read records" ?), and why is END not at the end ?

About the sort command wouldn't it fail on the ';' ? Do you know how to specify 'last field' of line with sort ? Or is something like :
| awk '{ printf substr($NF, 1, length($NF)-1);$NF = "";printf " %s\n",$0 }' | sort -n | awk '{ printf "%s%s;\n",$0,$1 }' | awk '{$1="";sub(/^ +/, "");printf "%s\n",$0}'
preferable ?

Thanks a lot again radoulov ^^
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JOIN(1) 						      General Commands Manual							   JOIN(1)

join - relational database operator SYNOPSIS
join [ options ] file1 file2 DESCRIPTION
Join forms, on the standard output, a join of the two relations specified by the lines of file1 and file2. If file1 is `-', the standard input is used. File1 and file2 must be sorted in increasing ASCII collating sequence on the fields on which they are to be joined, normally the first in each line. There is one line in the output for each pair of lines in file1 and file2 that have identical join fields. The output line normally con- sists of the common field, then the rest of the line from file1, then the rest of the line from file2. Fields are normally separated by blank, tab or newline. In this case, multiple separators count as one, and leading separators are dis- carded. These options are recognized: -an In addition to the normal output, produce a line for each unpairable line in file n, where n is 1 or 2. -e s Replace empty output fields by string s. -jn m Join on the mth field of file n. If n is missing, use the mth field in each file. -o list Each output line comprises the fields specifed in list, each element of which has the form n.m, where n is a file number and m is a field number. -tc Use character c as a separator (tab character). Every appearance of c in a line is significant. SEE ALSO
sort(1), comm(1), awk(1) BUGS
With default field separation, the collating sequence is that of sort -b; with -t, the sequence is that of a plain sort. The conventions of join, sort, comm, uniq, look and awk(1) are wildly incongruous. JOIN(1)

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