grep every even line 3

[tini1208]

hi all,

i don't know, if it is possible, but i want to extract every even line from a big file.

the file looks like this:

lon lat height
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
6 6 6
7 7 7

now, i want to extract line 2, 4, 6 etc.

is this possible? do i need linenumbers?

cheers

 

[p5wizard]

[tt]awk '!NR%2' /path/to/your/big/file[/tt]

or

[tt]awk 'NR%2'[/tt]

depending on if you're count from line 0 or line 1...


HTH,

p5wizard

 

[andy61]

p5wizard,
That is so beautiful and simple. It's the e=mc2 of awk. I had a solution also based on the modulo, but nothing so classy. As Antione de St Exupery said, you know you've achieved perfection, not when there's nothing more to add, but when there's nothing more to take away

 

[tini1208]

hi p5wizard

thank a lot for our answer.
the command awk '!NR%2' infile does not work, error: NR: Event not found

but the second command works very well!!!! thank a lot!

 

[p5wizard]

awk '!(NR%2)'

then?

It looks like bash history processing is getting in the way...

HTH,

p5wizard

 

[tini1208]

yes!!! awk '!(NR%2)' works very well!
thank you!