mjhjmtu

I would like to know how I can get the value of a node with the following paths:

config/global/resources/default_setup/connection/host
config/global/resources/default_setup/connection/username
config/global/resources/default_setup/connection/password
config/global/resources/default_setup/connection/dbname

from the following XML:

<?xml version="1.0"?>
<config>
 <global>
 <install>
 <date><![CDATA[Tue, 11 Dec 2012 12:31:25 +0000]]></date>
 </install>
 <crypt>
 <key><![CDATA[70e75d7969b900b696785f2f81ecb430]]></key>
 </crypt>
 <disable_local_modules>false</disable_local_modules>
 <resources>
 <db>
 <table_prefix><![CDATA]></table_prefix>
 </db>
 <default_setup>
 <connection>
 <host><![CDATA[localhost]]></host>
 <username><![CDATA[root]]></username>
 <password><![CDATA[pass123]]></password>
 <dbname><![CDATA[testdb]]></dbname>
 <initStatements><![CDATA[SET NAMES utf8]]></initStatements>
 <model><![CDATA[mysql4]]></model>
 <type><![CDATA[pdo_mysql]]></type>
 <pdoType><![CDATA]></pdoType>
 <active>1</active>
 </connection>
 </default_setup>
 </resources>
 <session_save><![CDATA[files]]></session_save>
 </global>
 <admin>
 <routers>
 <adminhtml>
 <args>
 <frontName><![CDATA[admin]]></frontName>
 </args>
 </adminhtml>
 </routers>
 </admin>
</config>

Also I want to assign that value to the variable for further use. Let me know your idea.

Using bash and xmllint (as given by the tags):

xmllint --version # xmllint: using libxml version 20703

# Note: Newer versions of libxml / xmllint have a --xpath option which 
# makes it possible to use xpath expressions directly as arguments. 
# --xpath also enables precise output in contrast to the --shell & sed approaches below.
#xmllint --help 2>&1 | grep -i 'xpath'

 sed '1d;$d')"
password="$(echo "cat /config/global/resources/default_setup/connection/password/text()" 

# output
# host: localhost
# username: root
# password: pass123
# dbname: testdb

In case there is just an XML string and the use of a temporary file is to be avoided, file descriptors are the way to go with xmllint (which is given /dev/fd/3 as a file argument here):

set +H
 
 xmllint --nocdata --shell /dev/fd/3 
set -H


# output
# host: localhost
# username: root
# password: pass123
# dbname: testdb

Although there are a lot of answers already, I'll chime in with xml2.

$ xml2 < test.xml
/config/global/install/date=Tue, 11 Dec 2012 12:31:25 +0000
/config/global/crypt/key=70e75d7969b900b696785f2f81ecb430
/config/global/disable_local_modules=false
/config/global/resources/db/table_prefix
/config/global/resources/default_setup/connection/host=localhost
/config/global/resources/default_setup/connection/username=root
/config/global/resources/default_setup/connection/password=pass123
/config/global/resources/default_setup/connection/dbname=testdb
/config/global/resources/default_setup/connection/initStatements=SET NAMES utf8
/config/global/resources/default_setup/connection/model=mysql4
/config/global/resources/default_setup/connection/type=pdo_mysql
/config/global/resources/default_setup/connection/pdoType
/config/global/resources/default_setup/connection/active=1
/config/global/session_save=files
/config/admin/routers/adminhtml/args/frontName=admin

With a little magic you can even set those as variables directly:

$ eval $(xml2 < test.xml | tr '/, ' '___' | grep =)
$ echo $_config_global_resources_default_setup_connection_host 
localhost

The following works when run against your test data:

 read -r host; read -r username; read -r password; read -r dbname; 
 < <(xmlstarlet sel -t -m /config/global/resources/default_setup/connection 
 -v ./host -n 
 -v ./username -n 
 -v ./password -n 
 -v ./dbname -n)

This puts the content into variables host, username, password and dbname.

A pure bash function, just for the unfortunate case when you are not allowed to install anything appropriate. This may, and probably will, fail on more complicated XML:

function xmlpath()

 local expr="$1//// "
 local path=()
 local chunk tag data

 while IFS='' read -r -d '<' chunk; do
 IFS='>' read -r tag data <<< "$chunk"

 case "$tag" in
 '?'*) ;;
 '!–-'*) ;;
 '![CDATA['*) data="$tag:8:$#tag-10" ;;
 ?*'/') ;;
 '/'?*) unset path[$#path[@]-1] ;;
 ?*) path+=("$tag") ;;
 esac

 [[ "$path[@]" == "$expr" ]] && echo "$data"
 done

Usage:

bash-4.1$ xmlpath 'config/global/resources/default_setup/connection/host' < MagePsycho.xml
localhost

Known issues:

• slow


• searches only by tag names


• no character entity decoding

You can make use of php command line interface coding in bash scripts to handle several complex scripts that actually span over multiple lines of coding. First, try to make your solution using PHP scripts, and then later on pass the parameters using CLI mode. Thus, you can get control over superb usages of XML parsers.

The environment seems that you can use PHP in client mode via ssh/shell access.

php -f yourxmlparser.php

Now, do all the things within your php file. Make use of command line parameters it can take.

You can even assign that return values to Shell environment to continue rest of your shell scripts.

And the other way is to use |grep option to match your required value within the xml file, if you are pretty sure of the structure of your xml file that does not change over time.

Using xmllint and the --xpath option, it is very easy. You can simply do this:

XML_FILE=/path/to/file.xml

HOST=$(xmllint --xpath 'string(/config/global/resources/default_setup/connection/host)' $XML_FILE
USERNAME=$(xmllint --xpath 'string(/config/global/resources/default_setup/connection/username)' $XML_FILE
PASSWORD=$(xmllint --xpath 'string(/config/global/resources/default_setup/connection/password)' $XML_FILE 
DBNAME=$(xmllint --xpath 'string(/config/global/resources/default_setup/connection/dbname)' $XML_FILE

If you need to get to an element's attribute, that's also easy using XPath. Imagine you have the file:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<addon id="screensaver.turnoff"
 name="Turn Off"
 version="0.10.0"
 provider-name="Dag Wieërs">
 ..snip..
</addon>

The needed shell statements would be:

VERSION=$(xmllint --xpath 'string(/addon/@version)' $ADDON_XML)
AUTHOR=$(xmllint --xpath 'string(/addon/@provider-name)' $ADDON_XML)