delete specific line

[dbase77]

Hi All,

How do I go about deleting specific line? Example, every 15 lines, I want to delete line. Thanks.

 

[PHV]

awk 'NR%15' /path/to/input > output

Hope This Helps, PH.
FAQ219-2884
FAQ181-2886

 

[feherke]

Hi

sed '15~15d' /input/file > /output/file

[gray]# or[/gray]

awk 'NR%15' /input/file > /output/file

[gray]# or with GNU sed[/gray]

sed -i '15~15d' /input/file

Feherke.

http://rootshell.be/~feherke/

 

[PHV]

Which flavor of sed admits this syntax: '15~15d' ?

 

[dbase77]

Hi,

I got error for both awk and sed.

using awk:
>>awk 'NR%88' file1 > /tmp/file2
awk: syntax error near line 1
awk: bailing out near line 1

using sed:
>>sed '15~15d' file1 > /tmp/file2
Unrecognized command: 15~15d

Any ideas? Thanks.

 

[feherke]

Hi

Hmm... I remember that ~ is a base functionality... That means not. Well, GNU [tt]sed[/tt] certainly knows it.

Feherke.

http://rootshell.be/~feherke/

 

[PHV]

Try nawk instead of awk.

Hope This Helps, PH.
FAQ219-2884
FAQ181-2886

 

[aigles]

GNU sed

The following address types are supported:

[COLOR=blue]number[/color] Match only the specified line [COLOR=blue]number[/color].

[COLOR=blue]first[/color]~[COLOR=blue]step[/color]
       Match  every  [COLOR=blue]step[/color]'th  line starting with line [COLOR=blue]first[/color].  For example, ``sed -n
       1~2p'' will print all the odd-numbered lines in the input  stream,  and  the
       address  2~5 will match every fifth line, starting with the second. (This is
       an extension.)

Jean-Pierre.

 

[feherke]

Hi

Try nawk instead of awk.

After my memory seems my precognition also gave up. I was sure you will suggest

awk 'NR%15[red]{print}[/red]' /path/to/input > output

Feherke.

http://rootshell.be/~feherke/

 

[dbase77]

Hi,

Thanks. nawk is working. I wonder why sed doesnt work. I guess I stick with nawk for now. Thanks again.

 

[PHV]

I wonder why sed doesnt work
In fact the "sed" solution provided isn't POSIX compliant (ie standard) but GNU extended.

 

[olded]

Eric Pement's sed one-liners page at:

http://www.student.northpark.edu/pemente/sed/sed1line52.txt

shows this sed solution:

# delete every 8th line
gsed '0~8d'                           # GNU sed only
sed 'n;n;n;n;n;n;n;d;'                # other seds