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Old 05-16-2008
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I tried using the command 'tac' . i get an error command not 'found'.. how do delete the last three lines from the file..please help
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Old 05-17-2008
era era is offline
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If you know the number of lines, subtract three and print up through that number.

Radoulov's solutions are superior, as usual, although they will read the entire file into memory at once, whereas the following basically operates the file a line at a time.

Code:
lines=$(wc -l <inputfile)
wanted=`expr $lines - 3`
head -n $wanted inputfile >outputfile
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Old 05-17-2008
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This is not memory-intensive, and will work.

Code:
cat filename | perl -ne 'push(@a, $_); print shift(@a, ) if  $#a >=3 ;'
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