unix and linux commands - unix shell scripting

cristalp · #1 09-09-2011 - Original Discussion by cristalp

I am learning AWK and quite fresh now.

My Q: How could I use AWK to print lines from e.g. first to 8th, or 5th to 9th?

Thanks!!!

ahamed101 · #2 09-09-2011 - Original Discussion by cristalp

Code:

#From 1 to 8
awk 'NR<=8 {print}' file

#Between 5 and 9 inclusive
awk 'NR>=5 && NR<=9 {print}' file

cristalp · #3 09-09-2011 - Original Discussion by cristalp

Quote:

Originally Posted by ahamed101

Code:

#From 1 to 8
awk 'NR<=8 {print}' file

#Between 5 and 9 inclusive
awk 'NR>=5 && NR<=9 {print}' file

You can use FNR if you have multiple files.
NR is the total number of records for all the files.
FNR is specific to each file bring processed. FNR will be reset when a new file comes in.

Try this code to find the difference

Code:

awk '{print NR "-" FNR}' file1 file2

--ahamed

Thanks Ahamed!! It works. But then, if I just want to print one line, say 9th line.

Code:

awk 'NR =9 {print}' FILENAME

durden_tyler · #4 09-09-2011 - Original Discussion by cristalp

Quote:

Originally Posted by cristalp

...

Code:

awk 'NR =9 {print}' FILENAME

gave me all the lines in the file. How can I just print one specific line according to line number then?
...

You have to compare and not assign.

Code:

$
$
$ cat f20
This is line 1
This is line 2
This is line 3
This is line 4
This is line 5
This is line 6
This is line 7
This is line 8
This is line 9
This is line 10
$
$ awk 'NR==9 {print}' f20
This is line 9
$
$
$ awk 'NR=9 {print}' f20
This is line 1
This is line 2
This is line 3
This is line 4
This is line 5
This is line 6
This is line 7
This is line 8
This is line 9
This is line 10
$
$

cristalp · #5 09-15-2011 - Original Discussion by cristalp

Quote:

Originally Posted by durden_tyler

You have to compare and not assign.

Code:

$
$
$ cat f20
This is line 1
This is line 2
This is line 3
This is line 4
This is line 5
This is line 6
This is line 7
This is line 8
This is line 9
This is line 10
$
$ awk 'NR==9 {print}' f20
This is line 9
$
$
$ awk 'NR=9 {print}' f20
This is line 1
This is line 2
This is line 3
This is line 4
This is line 5
This is line 6
This is line 7
This is line 8
This is line 9
This is line 10
$
$

Comparison is true only for line 9, hence it prints only line 9.
Assignment is true for each line, hence it prints each line.

tyler_durden

Thanks Tyler. Now I understand. Thanks for the excellent explanation!

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The Following User Says Thank You to ahamed101 For This Useful Post:
cristalp (09-15-2011)

The Following User Says Thank You to durden_tyler For This Useful Post:
cristalp (09-15-2011)

unix and linux commands - unix shell scripting

AWK print line no.x to line no.y

Shell Programming and Scripting