Shell Programming and Scripting

<n:tag_name1>
       <n:sub_tag1>val1</n:sub_tag1> 
       <n:sub_tag2>val2</n:sub_tag2>
</n:tag_name1>
<n:tag_name2>
       <n:sub_tag1>value</n:sub_tag1>
       <n:sub_tag2>value</n:sub_tag2>
</n:tag_name2>

grep '^<n' xmlfile

#!/bin/bash
#
# tags.sh

if [ ! $1 ]; then 
    echo "usage: `basename $0` <filename.xml> [output file]"
    exit 1
fi

tag_list=( $(grep -o -e "^\s*<\w.\w*>$" $1 | tr -d ' <>' | sed s/^n://g | sort -u ))
printf "\n%s%s\n" "tag_name=\"" "${tag_list[*]}\""

# Append to outfile
if [ $2 ]; then
    touch $2
    printf "%s:\n%s%s\n\n" "$1" "tag_name=\"" "${tag_list[*]}\"" >> $2
fi

### eof #

sed -n 's;^\(<[^/].*:\)\(.*\)>$;\2;p' file

awk '/^\// { L-- ; next }
/\/>/ { next }
L++ == 2 && /^n:/ { gsub(/^n:/, x); gsub(/[ >].*/, x) ; tags=tags" "$0 }
END{
  printf "tag_name=\"%s\"\n",substr(tags,2)
}' RS=\<  infile

<n:test1><empty/><name>Testing XML tag</name><ignore></ignore></n:test1><n:test2><empty/></n:test2>