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
JavaScript
x
#! /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
JavaScript
<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:
JavaScript
HOST="PC1" ConnectorType="" Timestamp="" FrameFormat="" RawData=""
HOST="PC1" ConnectorType="" Timestamp="" FrameFormat="" RawData=""
HOST="PC2" ConnectorType="" Timestamp="" FrameFormat="" RawData=""
HOST="PC2" ConnectorType="" Timestamp="" FrameFormat="" RawData=""
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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:
JavaScript
<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:
JavaScript
#! /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:
JavaScript
=============================
| 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"