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sed - use back reference in 2nd command

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# 1  
Old 08-07-2017
sed - use back reference in 2nd command
I have data that looks like this:
Code:
<Country code="US"><tag>adsf</tag><tag>bdfs</tag></Country><Country code="CA"><tag>asdf</tag><tag>bsdf</tag></Country>

I want to grab the country code save it, then drop each new "<..." onto a new line with the country code added to the beginning of each
So, the above would become:
Country - US
US asdf
US bsdf
US csdf
Country - CA
CA asdf
CA bsdf
CA csdf

I do this:
 sed 's/<Country code="\(..\)">/<Country - \1>/g;s/</\n&/g' inputfile.txt | grep Country
<Country - US>
</Country>
<Country - CA>
</Country>

But, if I try to add a reference to \1 to the second substitution, I get an error :
Code:
sed 's/<Country code="\(..\)">/<Country - \1>/g;s/</\n\1&/g' inputfile.txt | grep Country
sed: -e expression #1, char 54: invalid reference \1 on `s' command's RHS

ideas?
# 2  
Old 08-07-2017
Quote:
Originally Posted by JenniferAmon
I want to grab the country code save it, then drop each new "<..." onto a new line with the country code added to the beginning of each
What you need is not a (non-persistent) backreference but the (persistent) "hold space": this is a space where you can add, copy or pull text out of. I suggest you read the man page of sed to make yourself acquainted with the concept.

You best start by thinking through what you need to do for every type of line, i.e.:

a) lines with "country=" in them: load hold space with country code
b) all lines:
b1) split into tags (starting with "<")
b2) remove the tags themselves (as i took it from your sample output)
b3) add the content of the hold space to the begin of the pattern space

Note that you make your life a lot easier by using multi-line sed-programs. In principle you can the above also in a one-liner - like you can write a C program into one line too - but it would be very hard to read, even harder to understand and nigh impossible to debug.

I hope this helps.

bakunin
# 3  
Old 08-07-2017
Code:
sed 's/</\n</g' input_file | awk '
/<Country .*code=/ {
   country=$0;
   sub(".*code=\"*", "", country);
   sub("\".*", "", country);
   c=$0;
   sub(" .*", "", c);
   sub("< *", "", c);
   print c " - " country;
   next;
}
/<[^\/]*>/ {
   tag=$0;
   sub("<[^>]*> *", "", tag);
   print 1,country, 1,tag;
}
'

# 4  
Old 08-07-2017
The 2nd s resets the references.
It only works if its search pattern is empty i.e. taken from a previous match - but how to get a g option from a match?
The following works with one s but the number of <tag>s must be static, e.g. 2.
Code:
sed 's#<Country code="\(..\)"><tag>\([^<]*\)</tag><tag>\([^<]*\)</tag></Country>#Country - \1\
\1 \2\
\1 \3\
#g' inputfile.txt

Last edited by MadeInGermany; 08-07-2017 at 06:45 PM..
# 5  
Old 08-07-2017
Hi
With awk
Code:
awk 'BEGIN{FS="[><]";RS="<Country code="}/^$/{next};{gsub("\"","",$1);print "Country - "$1"\n"$1" "$4"\n"$1" "$8 }' inputfile

# 6  
Old 08-08-2017
And another one that works like the previous suggestions.
Code:
sed 's/</\
/g' inputfile.txt | sed '
\#^Country code="\(.*\)".*#{s##\1#;h;}
\#^tag>#!d
G;s#^tag>\(.*\)\n\(.*\)#\2 \1#
'

Because the first sed splits into lines, the second sed can take any number of <tag>s. Also it will tolarate(discard) other stuff in between (for example a <b> tag).
A Countr= header is left as an exercise.
# 7  
Old 08-08-2017
Try also
Code:
sed 's/<Country code="\(..\)">/\nCountry - \1/g; s/^\n//; s|</[^>]*>||g; s/<[^>]*>/\n/g' file | sed '/Country - / {p; s///; x; d}; G; s/\(.*\)\n\(.*\)/\2 \1/'
Country - US
US adsf
US bdfs
Country - CA
CA asdf
CA bsdf

Last edited by RudiC; 08-08-2017 at 10:04 AM..
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