URL:
<http://savannah.gnu.org/bugs/?func=detailitem&item_id=13212>
Summary: -newer only examines it's target once at the start
Project: findutils
Submitted by: None
Submitted on: Fri 05/27/2005 at 15:48
Category: find
Severity: 3 - Normal
Item Group: Wrong result
Status: None
Privacy: Public
Assigned to: None
Originator Name: Barry Dobyns
Originator Email: [EMAIL PROTECTED]
Open/Closed: Open
Release: 4.1.20
Fixed Release: None
_______________________________________________________
Details:
Actually Release 4.1.7, debian woody. Debian is always so up-to-date.
-newer only examines the target once
Consider the case where I'm trying to write a script that sets some "target"
file to the latest time of a large number of other files that I'm using find
to traverse.
I write
find $START -f -newer $TARGET -exec touch -r "{}" $TARGET ";"
but this only gets the time set to the last file that find examines that was
-newer than the $TARGET's mod time before the command began to execute.
My work-around for the line above is to execute until it produces no output,
but that's unpleasant, especially if the structure traversed by find is
large.
while true
do
findout=`find $START -f -newer $TARGET \
-exec touch -r "{}" $TARGET ";" -print | tail -1`
if [ -z $findout ] ; then break ; fi
done
After some reflection, I believe that the general case of this sort of
problem occur when I'm using -exec.
So, I can understand a line of argument that goes that mine is an exceptional
case, and the current behavior of -newer works well for everyone else in the
world. Indeed, in the general case where the action of the -exec command
does not modify one of the predicates, only taking the time once is a
reasonable and much-to-be-desired optimization.
Anywho, please consider changing the behavior of -newer such that it performs
the current behavior (check the time once) if and only if there are no -exec
arguments elsewhere in the predicate, and check the time every time if there
are -exec arguments elsewhere.
Or, (ugh!) add either another time test predicate that checks every time (for
use with find | xargs constructions).
_______________________________________________________
Carbon-Copy List:
CC Address | Comment
------------------------------------+-----------------------------
barry --AT-- dobyns --DOT-- com | Originator Email
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