Scripting: what is the easiest to extract a value in a tag of a XML file?

xml2 can convert xml to/from line-oriented format:

xml2 < pom.xml  | grep /project/version= | sed 's/.*=//'

Other way: xmlgrep and XPath:

xmlgrep --text_only '/project/version' pom.xml

Disadvantage: slow

Using python

$ python -c 'from xml.etree.ElementTree import ElementTree; print ElementTree(file="pom.xml").findtext("{http://maven.apache.org/POM/4.0.0}version")'
1.0.74-SNAPSHOT

Using xmlstarlet

$ xml sel -N x="http://maven.apache.org/POM/4.0.0" -t -m 'x:project/x:version' -v . pom.xml
1.0.74-SNAPSHOT

Using xmllint

$ echo -e 'setns x=http://maven.apache.org/POM/4.0.0\ncat /x:project/x:version/text()' | xmllint --shell pom.xml | grep -v /
1.0.74-SNAPSHOT