Im making a script to extract fields from a XML, now i got this and i need to make it work, i was trying with 2 for and greps and i need a little help with this
#! /bin/bash function charge_files () { XML="Prueba.xml"; if [ -f "$XML" ]; then echo "============================="; echo "| XML CHARGED |"; echo "============================="; else echo "============================="; echo "| XML NOT CHARGED |"; echo "============================="; fi } function extract () { #extract all from the file (not curr working) x=`grep "Host"` for $x in "$XML" do for LINEA in `cat $XML | grep "<Telegram" ` #LINEA guarda el resultado del fichero datos.txt do TIMESTAMP=`echo $LINEA | grep [Timestamp="*"] ` #Extracts TIMESTAMP FRAMEFORMAT=`echo $LINEA | grep [FrameFormat="*"]` #Extracts FRAMEFORMAT RAWDATA=`echo $LINEA | grep [RawData="*"]` #Extracts RAWDATA echo "$x $HOST $TIMESTAMP $FRAMEFORMAT $RAWDATA" >> output.logs #Shows result done done } charge_files extract
i got this xml withs this fields
<CommunicationLog xmlns="http://knx.org/xml/telegrams/01"> <RecordStart Timestamp="" Mode="" Host="PC1" ConnectionName="" ConnectionOptions="" ConnectorType="" MediumType="" /> <Telegram Timestamp="" Service="" FrameFormat="" RawData="" /> <Telegram Timestamp="" Service="" FrameFormat="" RawData="" /> <RecordStart Timestamp="" Mode="" Host="PC2" ConnectionName="" ConnectionOptions="" ConnectorType="" MediumType="" /> <Telegram Timestamp="" Service="" FrameFormat="" RawData="" /> <Telegram Timestamp="" Service="" FrameFormat="" RawData="" /> <RecordStop Timestamp="" /> </CommunicationLog>
and i want a output like this for make more comparations:
HOST="PC1" ConnectorType="" Timestamp="" FrameFormat="" RawData="" HOST="PC1" ConnectorType="" Timestamp="" FrameFormat="" RawData="" HOST="PC2" ConnectorType="" Timestamp="" FrameFormat="" RawData="" HOST="PC2" ConnectorType="" Timestamp="" FrameFormat="" RawData=""
Advertisement
Answer
there are many issues with the code.
- General:
- Indent your code, it makes it much simpler for you and others to debug and support the code.
- When writing a script, do it almost line per line, and test every line. Add echo of your variables, …
- Do not write a whole bunch of lines and then try to figure out why it does not work.
- Ex. the very first line in extract() does not work. If you try extract() with just that one line, do not move forward, debug that first.
- Prueba.xml:
- You have a RecordStart, then another RecordStart, than a RecordStop. Did you forget the RecordStop for the first RecordStart?
- I added test data because it is hard to debug with empty fields.
- charge_files:
- Does nothing else than check if the file exists. But fine.
- No need for ‘;’ on the echo commands, or the XML assignment. Removed.
- If the XML file is not present, your script will run regardless. I added an exit because the file needs to exist for the rest of the script.
extract:
- You cannot use for to iterate on lines like you tried to do. For will iterate on every word. Use the while like I put in my code.
- You need to loop on every line, look at my code. Your method with the grep Telegram would not differentiate between PC1’s Telegram lines and PC2’s Telegram lines.
- The grep command returns the entire line. So if you grep on a word in a line, it will not return a portion of the line, it will return the entire line.
- To extract parts of a line, you can use cut (like I did since your requirements are simple), awk, sed.
Assumptions:
- the lines always contain the same information, in the same order.
So here is the XML file I used for my tests:
<CommunicationLog xmlns="http://knx.org/xml/telegrams/01"> <RecordStart Timestamp="" Mode="" Host="PC1" ConnectionName="name1" ConnectionOptions="option1" ConnectorType="type1" MediumType="med1" /> <Telegram Timestamp="t1a" Service="s1a" FrameFormat="ff1a" RawData="rd1a" /> <Telegram Timestamp="t1b" Service="s1b" FrameFormat="ff1b" RawData="rd1b" /> <RecordStart Timestamp="" Mode="" Host="PC2" ConnectionName="name2" ConnectionOptions="option2" ConnectorType="type2" MediumType="med2" /> <Telegram Timestamp="t2a" Service="s2a" FrameFormat="ff2a" RawData="rd2a" /> <Telegram Timestamp="t2b" Service="s2b" FrameFormat="ff2b" RawData="rd2b" /> <RecordStop Timestamp="stoptimestamp" /> </CommunicationLog>
And here the script:
#! /bin/bash function charge_files () { XML="Prueba.xml" if [ -f "$XML" ]; then echo "=============================" echo "| XML CHARGED |" echo "=============================" else echo "=============================" echo "| XML NOT CHARGED |" echo "=============================" exit 1 fi } function extract () { host='' while IFS= read -r line; do # Find if it is a RecordtStart line if [ $(echo $line | grep -c "RecordStart") -eq 1 ] then # If host == '', then it is the first host we see. # Otherwise, we are changing host, so print an empty line if [ "$host" != '' ] then echo "" fi # Collect the host information host=$(echo $line | awk '{print $4}' | cut -d'"' -f2) # Collect the ConnectorType information connectortype=$(echo $line | awk '{print $7}') # Done with this loop in the while, move on to the next continue fi # Find if it is a Telegram line if [ $(echo $line | grep -c "Telegram") -eq 1 ] then # Collect the Timestamp information timestamp=$(echo $line | awk '{print $2}') # Collect the FrameFormat information frameformat=$(echo $line | awk '{print $4}') # Collect the RawData information rawdata=$(echo $line | awk '{print $5}') # Print the information echo "HOST="$host" $connectortype $timestamp $frameformat $rawdata" # Done with this loop in the while, move on to the next continue fi done <$XML } charge_files extract
Which produced this output:
============================= | XML CHARGED | ============================= HOST="PC1" ConnectorType="type1" Timestamp="t1a" FrameFormat="ff1a" RawData="rd1a" HOST="PC1" ConnectorType="type1" Timestamp="t1b" FrameFormat="ff1b" RawData="rd1b" HOST="PC2" ConnectorType="type2" Timestamp="t2a" FrameFormat="ff2a" RawData="rd2a" HOST="PC2" ConnectorType="type2" Timestamp="t2b" FrameFormat="ff2b" RawData="rd2b"