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get all entries after particular date !!

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# 8  
Old 11-23-2007
Originally Posted by radoulov
f is a variable, its name is arbitrary (it can be any valid variable name).
In Awk uninitialized variables have the numeric value zero.
When the first filed of the current record matches our pattern ($1==dt),
we set f to 1 (or any other number != 0 - for Awk 0 and null mean false,
all others mean true). We check every record
(first check, then set, so the record that matches
is not printed), we print the records once the variable is set to 1 (true).

It goes like this:


record: 2007-10-18 
code: f 
action: checks f is not 0 -> f==0 (uninitialized yet) -> do nothing
code: $1==dt{f=1}
action: $1!=dt -> do nothing

record: 2007-10-19
code: f
action: checks f is not 0 -> f==0 (uninitialized yet) -> do nothing
code: $1==dt{f=1}
action: $1==dt -> set f to 1(true) --> initialized here!

record: 2007-10-20
code: f
action: checks f is not 0 -> f==1 -> default action: print the current record
code: $1==dt{f=1}
action: $1!=dt -> do nothing (even if $1==dt, we will set again f to 1,
but it doesn't matter :)

Thanks a lot for this radoulov :-)


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