Re: for loop (?)

From: Ed Morton (morton_at_lsupcaemnt.com)
Date: 01/29/04 

Date: Thu, 29 Jan 2004 14:49:37 -0600

Icarus Sparry wrote:
<snip>
> awk 'NR>'$line' {exit}
> { f="client" NR "_out" ; print $1 $2 > f ; close(f)}' out

Whenever possible, you should use awk variables in awk scripts instead
of shell variables to avoid problems when those shell variables include
special characters (\, #, newline, etc.), so do this instead:

awk -v line="$line" 'NR>line {exit}
{ f="client" NR "_out" ; print $1 $2 > f ; close(f)}' out

or (if -v not supported by your version of awk):

awk 'NR>line {exit}
{ f="client" NR "_out" ; print $1 $2 > f ; close(f)}' line="$line" out

<snip>
> awk 'BEGIN { for(i=1;i<='$1';++i) { print i ; } exit }'

awk -v max="$1" 'BEGIN { for(i=1;i<=max;++i) print i }'

or

awk '{ for(i=1;i<=max;++i) print i }' max="$1" <<!

!

The latter needs that syntax because assigning variables without -v
means those variables don't apply to the BEGIN section so we have to
move the for loop to the main body and provide some kind of input (I
chose a here document with a blank line).

The specific above cases would probably work fine as originally written,
but it's good to get into the habit of using awk variables so there's no
surprises down the road.

        Ed.