Search all xml files recursively in directory for a specific tag and grep the tag's value

Question

Ubuntu 14.04 Trusty Tahr.

Suppose I have directory called 'testmag' which may contain 100s of xml files and directories which in turn contain many xml files as well. I don't know names of any xml files but I know one of them contains tag <dbname>....</dbname>.

Now how to find the file containing the aforementioned tag and grep the tag's value as output in terminal

Answer 1

Here is a solution with find that will also output the filenames of files containing a match:

find . -name "*.xml" -exec grep '<dbname>' {} \;             \
                     -exec echo -e {}"\n" \;                 \
                     | sed 's/<dbname>\(.*\)<\/dbname>/\1/g'

Explanation

1. find . -name "*.xml" find all xml files recursively from current directory
2. -exec grep '<dbname>' {} \; on each file search for pattern <dbname>
3. -exec echo -e {}"\n" \; echo filename + new line (-e option makes echo interpret \n)
4. | sed 's/<dbname>\(.*\)<\/dbname>/\1/g' pipe output to sed to print only the field contained between the <dbname></dbname> tags.

NOTE1: you can format output in your echo -e ... to have results for each file clearly laid out, e.g. by adding new lines, or lines of underscore, whatever suits your need.

NOTE2: path to each file will be given relatively to . (e.g. ./subfolder1/file.xml). If you want absolute path, go for find $PWD -name ....

Answer 2

Using a proper XML parser to parse XML:

shopt -s globstar nullglob
for file in **/*.xml; do 
    dbname=$(xmlstarlet sel -t -v '//dbname' "$file")
    [[ -n "$dbname" ]] && printf "%s\t%s\n" "$file" "$dbname"
done

Answer 3

Using find with xq:

find testmag -type f -name '*.xml' -exec xq -r '..|(.dbname? // empty)' {} +

This would find all regular files with names matching *.xml in or below the testmag directory. For batches of these, xq would be called to extract the value of every dbname node found in those documents.

xq is a jq-like XML parser that is distributed with yq from https://kislyuk.github.io/yq/

---

Would you need the filenames of all XML files that have this node, you could use

find testmag -type f -name '*.xml' -exec xq -e '..|(.dbname? // empty)' {} \; -print

... although this would be a fair bit slower than just extracting the value of the node as we need to invoke xq once for each file.

Answer 4

Suppose we have directory XMLS containing these files:

cat XMLS/file1
foo bar <dbname>target</dbname> baz
foo foo

cat XMLS/file2
<name>notarget</name>

I would use this command:

grep -r '<dbname>' XMLS/ | sed 's/.*<dbname>\(.*\)<\/dbname>.*/\1/'
target

Which, as you can see, returns the value inside the <dbname> tags. And not the value inside the <name> tags.

The -r flag for grep searches recursively.

sed strips the string of everything except the value target.