Shell Programming and Scripting

 
sed -n '/\<String\>/,/\<\/String\>/p' yourfile

#!/usr/bin/env bash

# @(#) s1	Demonstrate extract data from XML file, xml_grep.
# Reference for XPath: http://en.wikipedia.org/wiki/XPath_1.0
# xml_grep: http://xmltwig.com/tool/

echo
set +o nounset
LC_ALL=C ; LANG=C ; export LC_ALL LANG
echo "Environment: LC_ALL = $LC_ALL, LANG = $LANG"
echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version "=o" $(_eat $0 $1) xml_grep
set -o nounset
echo

FILE=${1-data1}

echo " Data file $FILE:"
cat $FILE

echo
echo " Results:"
xml_grep --text_only --cond '*[@name="data1"]/String' $FILE

exit 0

% ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0 
GNU bash 3.2.39
/usr/bin/xml_grep version 0.7

 Data file data1:
<project>
<key name="data1">
<String>abcdef</String>
<String>abcdef1</String>
<String>abcdef2</String>
</key>

<key name="data2">
<String>abcdefg</String>
<String>abcdefg1</String>
<String>abcdefg2</String>
<String>abcdefg3</String>
</key>
</project>

 Results:
abcdef
abcdef1
abcdef2

 
sed -e 's/\(<[^<][^<]*>\)//g' file.xml
 
OR
 
sed -e 's/\(<[^<][^<]*>\)//g; /^$/d' file.xml

awk 'BEGIN{RS="";FS="</String>"}
/data1/{
 for(i=1;i<=NF;i++){
    if($i ~ /String/){
        gsub(/.*String>/,"",$i)
        print $i
    }    
 } 
}' file