how to separate odd even line# in a file

skd · #1 (**permalink**) 08-25-04, 15:17

i am newbie here and looks that awk doesnot support modulus function or i am having some syntax error

> fileE
> fileO
#
#awk '{ for ( i = 1,I<NR,i++ )
# if (NR%2) == 0) print $0 >> fileE else print $0 >> fileO
# }' testNC
#
awk -f sd.awk testNC

// my purpose is to separate out even and odd lines of file into two files

vgersh99 · #2 (**permalink**) 08-25-04, 15:33

sure it does:

Code:

FNR%2 { print >> fileO ; next} {print >> fileE }'

skd · #3 (**permalink**) 08-25-04, 16:08

that looks pretty simple. i am still making some mistake

awk ' FNR%2 { print >> fileO ; next} {print >> fileE }' testNC
//

awk: A print or getline function must have a file name.
The input line number is 1. The file is testNC.
The source line number is 1.

vgersh99 · #4 (**permalink**) 08-25-04, 16:15

Code:

nawk -v fileO=myOdd -v fileE=myEven 'FNR%2 { print >> fileO ; next} {print >> fileE }' testNC

skd · #5 (**permalink**) 08-25-04, 16:22

thank you. it worked.

not sure why variable needed here for filename. is this possible using sed ?

vgersh99 · #6 (**permalink**) 08-25-04, 17:10

Quote:

Originally Posted by skd

thank you. it worked.

not sure why variable needed here for filename. is this possible using sed ?

The variables are used so that the filenames are NOT hard-wired in the script itself, but rather supplied on the command line - this is simply a matter of a personal taste.

The same can be re-written as:

Code:

nawk 'FNR%2 { print >> "fileO" ; next} {print >> "fileE" }' testNC

I cannot think of a way to do in sed, but I've been wrong before.

vgersh99 · #7 (**permalink**) 08-25-04, 17:19

or you can do it using ksh:

Code:

#!/bin/ksh

sed = testNC | sed 'N;s/\n/:/' | while IFS=: read num line
do
   (( num % 2 )) && echo "$line" >> "fileO" || echo "$line" >> "fileE"
done

skd · #8 (**permalink**) 08-26-04, 08:22

Thanks man, I liked your new awk solution.

Thanks for all your time and help.

Damian Ibbotson · #9 (**permalink**) 08-26-04, 09:48

Quote:

Originally Posted by vgersh99

I cannot think of a way to do in sed, but I've been wrong before.

You could use the holdspace to determine if it is odd or even.
In the example below, I assume that if the holdspace is empty, it is an odd line. I would then substitute the empty string for a "." , swap back to the pattern space, output the value of pattern space to "oddFile" and then branch to the end of the script. For the next line, the holdspace now contains a ".", so the script executes ths second block which does the opposite (blanks out the holdspace and writes to "evenFile").

Personally, I'd stick with awk!

Code:

sed -n 'x
/^$/{
s/^/./
x
w oddFile
b theEnd
}
/./{
s/.//
x
w evenFile
}
:theEnd' inputFile

skd · #10 (**permalink**) 08-26-04, 10:49

awk solutions seems short and straight to me.
but i appreciate you showing and explaining your sed solution.
Thanks Damian & vgersh99

Internet Services

Web Development

Digital Marketing

Consumer Tech