Display a certain line of a file 1

[TSch]

Hi folks,

I'd like to display certain lines of a textfile and only that certain line.

e.G.

Textfile
---------
machine number
display type
hardware key
serial number

-> Now if I choose to display the third line the output shall say "hardware key" or if I choose to display the first line the output shall say "machine number".

Problem is (at least as far as I know) that tail is only able to display the first or last line or several last lines, etc. but NOT only one specific line in the middle of the file ...

How could this be done ?

Regards
Thomas

 

[feherke]

Hi

To display line 3 just use [tt]head[/tt] and [tt]tail[/tt] together :

head -3 /input/file | tail -1

Or you can use an alternative :

sed -n '3p' /input/file

[gray]# or[/gray]

awk 'NR==3' /input/file

[gray]# or[/gray]

perl -ne 'print if$.==3' /input/file

[gray]# or[/gray]

ruby -ne 'print if $.==3' /input/file

The speed optimized versions of the above alternatives :

sed -n '3{p;q}' /input/file

[gray]# or[/gray]

awk 'NR==3{print;exit}' /input/file

[gray]# or[/gray]

perl -ne 'if($.==3){print;exit}' /input/file

[gray]# or[/gray]

ruby -ne 'if $.==3:print;exit end' /input/file

Although not elegant, the [tt]head[/tt] & [tt]tail[/tt] solution was still the fastest, when I measured their speed last time.

Feherke.

http://free.rootshell.be/~feherke/

 

[TSch]

Perfect !
Thanks a lot