Output specific line in file

cgkee · 09-15-2009, 02:18 AM

I need to have a look at a specific line (355) in a file that is reporting an error. Can someone tell me how to do this?

cgkee · 09-15-2009, 02:38 AM

I think I have answered the question myself:

Code:

head -N file | tail -1

Where N is the line number you wish to view, and file is the filename
but if any experts then have additional useful tips that this often leads on to, I would be delighted to hear from you!

lutusp · 09-15-2009, 02:44 AM

Quote:

Originally Posted by cgkee

I think I have answered the question myself:

Code:

head -N file | tail -1

Where N is the line number you wish to view, and file is the filename
but if any experts then have additional useful tips that this often leads on to, I would be delighted to hear from you!

It's not an uppercase 'N' but lowercase, and Linux commands almost always care about case.

Another approach in a situation like this is to find something about the specific error message's content that's unique, like certain words or numbers, and filter on that instead of the line number, which is typically more difficult to pinpoint. This had the added advantage that any similar error messages will appear in the result.

colucix · 09-15-2009, 02:44 AM

Here are two additional ways using sed and awk:

Code:

awk 'NR==355' file
sed -n 355p file

colucix · 09-15-2009, 02:48 AM

Quote:

Originally Posted by lutusp

It's not an uppercase 'N' but lowercase, and Linux commands almost always care about case.

I think the OP meant N for integer, using the old posix standard. Indeed, better to do as you suggest:

Code:

head -n355 file | tail -1

that assures portability to newer systems that discarded compatibility with the old standard.

cgkee · 09-15-2009, 03:08 AM

I was indeed using N as an integer, and did not include it in the command, so to get line 355 I did the following

Code:

head -355 file | tail -1

but some of colucix's suggestions are even shorter and easier.

Thank you all for your quick responses and help