UNIX for Dummies Questions & Answers

Hi All,

pretty simple on, i have a text file or what ever with several lines:

one
two
three

How do i select a specific line by line number. Looked in cut and grep and cant find anything.

Thanks Chris.

Hi Chrish,

To list a specific line in a file, you shall use these commands.

line number =5

awk 'NR == 5' <file name>
sed -n '5q' <file name>
sed -n '6q;5p' <file name>
head -5 <filename>|tail -1 <filename>

Hope it will work,
bye
Siva

Hi Siva,

Welcome to UNIX forums.

This is a pretty good idea: But, I think there is a typo error, should be:

Code:

head -5 <filename>|tail -1

Good work...

Regards,
Tayyab

Hi,
There is a typo in sed -n '5q' <file name>. Actually, the command that is running fine is :
sed -n '5p' <file name>.

Also, clarify one more thing, what is the use of 'q' in sed command. I have seen the man pages, but couldn't find any. Also, if I am giving:
sed -n '10q;5p' <file name>, or
sed -n ';5p' <file name>, or
sed -n '5q;5p' <file name>

then also the result is same. Anybody, plz clarify !!!

Actually "5q;5p" is not the same as 10q;5p or ;5p. The last 2 would print line number 5. In the first case, it would not.

As such you would not notice the difference. The difference in terms of performance is much more significant when the input file is HUGE say a million lines in the file. In that case, "10q;5p" means, read the first 10 lines, and then print the 5 line. ";5p" would read million lines and then print the 5th line.