Sstrhsrtj

I want a command to strip an XML-Header and Footer from a file:

<?xml version="1.0" encoding="UTF-8"?>

<conxml>

<MsgPain001>

    <HashValue>A9C72997C702A2F841B0EEEC3BD274DE1CB7BEA4B813E030D068CB853BCFECA6</HashValue>

    <HashAlgorithm>SHA256</HashAlgorithm>

    <Document>

                ...

    </Document>

    <Document>

                ...

    </Document>

</MsgPain001>

</conxml>

...

Should become just

<Document>

         ...

    </Document>

    <Document>

          ...

    </Document>

(note the indenting, the indent of the first document-tag should be stripped of.

This sounds like a (greedy) regex

<Document>.*</Document>

But I don't get it due to the linefeeds.

I need it in a pipe to compute a hash over the contained documents.

Using sed:

 sed -n '/<Document>/,/</Document>/ p' yourfile.xml

Explanation:

• 
  -n makes sed silent, meaning it does not output the whole file contents,


• 
  /pattern/ searches for lines including specified pattern,


• 
  a,b (the comma) tells sed to perform an action on the lines from a to b (where a and b get defined by matching the above patterns),


• 
  p stands for print and is the action performed on the lines that matched the above.

Edit: If you'd like to additionally strip the whitespace before <Document>, it can be done this way:

 sed -ne '/ <Document>/s/^ *//' -e '/<Document>/,/</Document>/ p' yourfile.xml

To prevent text from being stripped between </Document> and the next <Document> you may have to use a series of sed commands (cf. Gilles' comment above).

Essentially sed reads the entire file into the hold buffer (so that the file contents can be treated as a single line) and marks the first and last Document tags for further processing.

# version 1

# marker: HERE

cat file.xml | 

sed -n '1h;1!H;${;g;s/(<Document>.*</Document>)/HERE1HERE/g;p;}' | 

sed -n -e '/HERE<Document>/,/</Document>HERE/ p' | 

sed -e 's/^ *HERE(<Document>)/1/' -e 's/(</Document>)HERE *$/1/'



# version 2    (using the Bash shell)

# marker: $'01'

cat file.xml | 

sed -n $'1h;1!H;${;g;s/\(<Document>.*<\/Document>\)/01\101/g;p;}' | 

sed -n -e $'/01<Document>/,/<\/Document>01/ p' | 

sed -e $'s/^ *01//' -e $'s/01 *$//' | 

cat -vet

... but I guess all this could be done more elegantly (& reliably) using xmlstarlet!