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Full Discussion: read file backwards
Top Forums Shell Programming and Scripting read file backwards Post 302137957 by bluemoon1 on Thursday 27th of September 2007 11:33:47 PM
Old 09-28-2007
read file backwards

Assume file1 contains a list of strings.
My first script is scanning the file and deals with the lines with a certain patern in it:

grep 'somepatern' file1 \
while read LINE ; do
doSomethingAboutIt
done

Now, I need a second script that deals with the same lines (& do something differently) but in the opposite order; the last line found in the file with that patern shuld be handled first.

Please help me. Thanks so much!!!

Last edited by bluemoon1; 09-28-2007 at 12:36 AM.. Reason: typo
 

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COMBINE(1)																COMBINE(1)

NAME
combine - combine sets of lines from two files using boolean operations SYNOPSIS
combine file1 and file2 combine file1 not file2 combine file1 or file2 combine file1 xor file2 _ file1 and file2 _ _ file1 not file2 _ _ file1 or file2 _ _ file1 xor file2 _ DESCRIPTION
combine combines the lines in two files. Depending on the boolean operation specified, the contents will be combined in different ways: and Outputs lines that are in file1 if they are also present in file2. not Outputs lines that are in file1 but not in file2. or Outputs lines that are in file1 or file2. xor Outputs lines that are in either file1 or file2, but not in both files. "-" can be specified for either file to read stdin for that file. The input files need not be sorted, and the lines are output in the order they occur in file1 (followed by the order they occur in file2 for the two "or" operations). Bear in mind that this means that the operations are not commutative; "a and b" will not necessarily be the same as "b and a". To obtain commutative behavior sort and uniq the result. Note that this program can be installed as "_" to allow for the syntactic sugar shown in the latter half of the synopsis (similar to the test/[ command). It is not currently installed as "_" by default, but you can alias it to that if you like. SEE ALSO
join(1) AUTHOR
Copyright 2006 by Joey Hess <joey@kitenet.net> Licensed under the GNU GPL. moreutils 2012-04-09 COMBINE(1)
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