Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

Remove every third line from a file

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Remove every third line from a file
# 1  
Old 01-31-2006
Remove every third line from a file
I need to remove every second and every third line from a file. My idea was to do it in two operations. First every third line, then every second line. The problem is that i can't find out how to do it. I tried to look for some sed oneliners, but couldn't find any.

Suggestions?
# 2  
Old 01-31-2006
awk 'NR%3 != 0' filename

in the same way, change 3 as 2 to remove 2nd line from the file
# 3  
Old 01-31-2006
Is this what you mean?

Code:
$ cat bistru.txt
line 1
line 2
line 3
line 4
line 5
line 6
line 7
line 8
line 9
$ sed -n 'p;N;N' bistru.txt
line 1
line 4
line 7
$

Cheers
ZB
# 4  
Old 01-31-2006
Thanks, both worked perfectly!

BTW, zazzybob, i'm not able to understand the syntax rather well. Do You mind giving a short explanation? I understand '-n' and that 'p' overruns the '-n'. From man sed i found that 'n' or 'N' means that the next line is input into the pattern space, implying that the line is suppressed. Am i completely wrong here, or?
# 5  
Old 01-31-2006
Quote:
Originally Posted by mahendramahendr
awk 'NR%3 != 0' filename

in the same way, change 3 as 2 to remove 2nd line from the file
in one shot it can be done,

Code:
awk 'NR % 3 == 1' filename

Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

Remove first line of file

How can I use bash to remove the first line of a file? (3 Replies)
Discussion started by: locoroco
3 Replies

2. Shell Programming and Scripting

Remove line from file and read file line by line

I have a file output.txt. File looks like this name1 10 name2 2 name3 5 I get a number n and I need to remove all lines which has number (after name) smaller or equal to n number. After that I need to write lines from file and my output must be like this: Output: 'name1 10' Output: 'name2... (1 Reply)
Discussion started by: kubo12312
1 Replies

3. Shell Programming and Scripting

How to remove last line of the file

Hi, unix gurus, I need to remove last line of the file. anybody can help me thanks in advance (7 Replies)
Discussion started by: ken002
7 Replies

4. Shell Programming and Scripting

Remove first line of file

Is there an easy way to remove the first line of a file so that the file: aaron benjamin cecilia daniel elliot fernando would become benjamin cecilia daniel elliot fernando (4 Replies)
Discussion started by: locoroco
4 Replies

5. Shell Programming and Scripting

Remove line from file

Hi!!! When I use vi editor my file looks like this: aaa2: 123.45^M aaa1: 11.34^M aaa3: aaa3: 15.56^M How to remove only line 3 ??? Thanks!!! (7 Replies)
Discussion started by: tdev457
7 Replies

6. Shell Programming and Scripting

Remove a line from a file

Hi ,guys. I have one question: I want to write a script which removes a line with certain string from a file, for example The name of the file is: "passwd", the contents of it is below: ************************* ... brownj2:x:5000: hynesp:x:5001: leeb:x:5002 dioxna:x:5003 ... ... (2 Replies)
Discussion started by: daikeyang
2 Replies

7. UNIX for Dummies Questions & Answers

remove a line within a file

Hi all, i have a text file similar to belowA1 A2 A3 B1 ... .... *** # first occurance B1 ... .... *** # second occurance B1 ... .... *** # third occurance My desired output is B1 ... .... *** # second occurance B1 ... .... *** # third occurance I want to remove the first line that is after... (3 Replies)
Discussion started by: new2ss
3 Replies

8. Shell Programming and Scripting

How to remove last line of the file

hi sir, i need help..how to remove last line of the each file for example i have files a.txt ,b.txt and so on..i wanted to delete last list of each file..the patten not same for each file..any help? thanks in advance (3 Replies)
Discussion started by: mani_um
3 Replies

9. Shell Programming and Scripting

Remove header(first line) and trailer(last line) in ANY given file

Hi, I need some help in removing the header (first line) and the trailer (last line) in a give file... The data file actually comes in EBCDIC format and I converted it into ASCII.. Now I need to strip off the first line and the last line.. I think we can use sed to do something like this:... (2 Replies)
Discussion started by: madhunk
2 Replies
Login or Register to Ask a Question