UNIX for Advanced & Expert Users

Another note matrixmadhan...

I think the code still changes line c even if there's no space character on that line...i mean if there's a numerical value between the tags there should be no substitution. (e.g. <tag: pnum>123 <tag: pnum> )

to repeat the requirements:
........
I'd like to change the third line or line c to " <tag:XXXX> <tag:XXXX> " if and only if:

1. line a contains the word CC between the tags "<tag: ptype>"
2. there is a space character between the tags "<tag: pnum>" in line c ( i.e. "<tag: pnum> <tag: pnum>" )
......

>cat file
<tagptype>CC<tagptype>
<tagpdescr>International<tagpdescr>
<tagpnum> <tagpnum>

>output of the command posted
<tagptype>CC<tagptype>
<tagpdescr>International<tagpdescr>
<tag:XXXX> <tag:XXXX>

The third line is changed only based on the values available in the first line
and the first line has got 'CC' in it and hence it is changed

Am sorry! If hadnt understood your requirement properly!

My fault...I didn't present a good example

anyways..here is a sample file:
> cat file

<tagptype>CC<tagptype>
<tagpdescr>International<tagpdescr>
<tagpnum> <tagpnum>

<tagptype>CC<tagptype>
<tagpdescr>local<tagpdescr>
<tagpnum>13.78<tagpnum>

Here's the supposed output:

<tagptype>CC<tagptype>
<tagpdescr>International<tagpdescr>
<tagXXXX> <tagXXXX>

<tagptype>CC<tagptype>
<tagpdescr>local<tagpdescr>
<tagpnum>13.78<tagpnum>

Code:

awk 'BEGIN{set=0} { if( $0 ~ "^<tagptype" && $0 ~ ">CC<" ) { set=1; print } else { if ($0 ~ "<tagpnum> <" && set == 1 ) { print "<tag:XXXX> <tag:XXXX>"; set=0 } else { print } }  }' file

Change the search pattern!

Code:

sed "/<tagptype>CC<tagptype>/{n;n;/> *</s/.*/<tagXXXX> <tagXXXX>/;}" file

This is what I've been looking for. Thanks Anbu23 and matrixmadhan!!!