Shell Programming and Scripting

Hi Guys,
I am new to unix.
Actually i want help in writing an single command where
i can actually read specific line number in file where the line number will be passed to command as parameter.

ex.
1 a
2 b
3 c
4 d

And to my command i pass as 2.
so i should get output as 2 b

---------- Post updated at 05:28 PM ---------- Previous update was at 05:25 PM ----------

i implemented this by below code

Code:

head -n parameter | tail -n 1

but if file is big this will degrade the performance.

But i need to have this as in single line only.
And if possible without awk.

Code:

sed '2!d' yourfile

Number = your wanted line number.

Hi.

Code:

n=3
$ sed "${n}!d" file
or
$ sed -n "${n}p" file
or
awk -v n=$n 'NR == n' file

Hi zaxxon,

Thanks for reply.
Can you please explain me what this command does.
i tried reading man sed in shell but it didn't help

Code:

$ num=3
$ gawk -v n=$num 'NR==n{print;exit}' file

num=3
cat -n samplefile.txt | grep " $num" | cut -f2

You might want to check websites for sed tutorials etc. or get a good book about it like sed&awk from O'Reilly.

It means
The opposite would have been:

Code:

sed -n '2p' infile

Which have meant to not print out every line but only the address you want to process.