Delete last two lines

[Rodney Hills]

Here is a perl one-liner that only requires one pass through the file.

perl -ne 'push(@last2,$_); if (scalar @last2 > 2) { print shift @last2}'

By pushing each line onto a stack this script will not print the last 2 lines.

HTH

-- Rod Hills

[Rodney Hills]

Parmy,

Assigning points to indicate which solution you think works the best is what helps the forum help others...

-- Rod Hills

[Rick Garland]

cat $file | sed '1,2d'

[Hein van den Heuvel]

Here is a one-pass in awk which does no create a temp file.
It uses a 'circular buffer' of the target 'missing line' count 'L'.
This is done with an array 'line' indexed by the current record number (NR) modulus that L.
You provide a desired value for L as argument.
We start printing from the array only after L lines have come by, 'falling behind' by L lines.

Sounds tricky? Here is the 'one line' code:

awk -vL=2 '{if(NR>L){print line[(NR-L)%L];line[NR%L]=$0}}' your-file


Hein.

[Elmar P. Kolkman]

Hein, your solution is a variant of my awk solution... but my mathematic mind says you need to remove the -L in your solution. It does nothing in the end... since (NR-L)%L equals NR%L.
And you have a closing curly bracket wrong, resulting in missing the first lines...

So the right solution would be:

awk -vL=2 '{if(NR>L){print line[NR%L];}line[NR%L]=$0}' my_file

[Elmar P. Kolkman]

Strange point assignment... I've tested the highest rated solution, but it doesn't seem to work. At least nog on the /etc/passwd files I have on Linux and HP-UX... But it could be me...

[Bharat Katkar]

It looks like Parmy is taking it very lightly and on the contrary all the responders are struggling to be as perfect as possible..

[Hein van den Heuvel]

Elmar> Hein, your solution is a variant of my awk solution...

Ayup, just a touch more general purpose. I had missed the awk part of your solution.

Elmar> but my mathematic mind says you need to remove the -L in your solution.

Ayup, a simplication I overlooked this time.

Elmar> It does nothing in the end... since (NR-L)%L equals NR%L.

Ayup, other then to make the code more clear.

Elmar> And you have a closing curly bracket wrong, resulting in missing the first lines...

Ooops! Thanks for catching that.

Groetjes,
Hein.