UNIX for Dummies Questions & Answers

Hi friends,

I have a large of this similiar data:

<INF n="data" z="22" />

I need to get:

data 22

please let me know if you can help!

If you have them all in a file, you could try:-

Code:

cut -f2,4 -d"\"" filename | tr "\"" " "

I hope that this helps,

Robin
Liverpool/Blackburn
UK

Code:

$ echo '<INF n="data" z="22" />' | awk '/<INF/ { $NF=""; $1=""; print }' | xargs -n 2 echo | while IFS=" =" read A B C D ; do echo $B $D ; done
data 22

$

Code:

cut -f2,4 -d"\"" filename | tr "\"" " "

This great coding!!!! Thanks!

You are welcome. Does it need an explanation (especially the backslahes) ??



Robin

Robin,

I would love an explanation. Still trying to learn the commands so don't be afraid to "dumb" it down

Thanks

So the code supplied:-

Code:

cut -f2,4 -d"\"" filename | tr "\"" " "

If you are not familiar then it probably looks a bit serious. We'll break it down. The vertical bar, known as a pipe mark, joins the output from one operation to the input of the next operation. In this way, you can string a number of processes together. It saves you having to write an output file with each operation to then be read in by the next. All processing happens in memory so saving the I/O effort and time.

From this, you can see you have two statements joined up. The first part reads the file filename and slices it up. The flags on the cut command give the instructions. -d tells cut what the delimiter is (how to count along fields in a record). In our case, we're counting by a " however as this is a special character to we have to mark it as such with an Escape character. The blackslash \ tells the shell not to interpret the " and just pass it as it is into the cut command. If we didn't do this, it would try to interpret the -d flag as open-double-quote, close-double-quote (so nothing), open double-quote, space, filename and then get very confused because it's only expecting a single character. You would probably get an error for ending on an open-double-quote andyway as it will be waiting for the next double-quote to make a valid statement.
The -f2,4 states that we want fields 2 & 4 only.

Slightly annoyingly, this uses the existing delimited of " to separate the fields in the output, so we pass this as input to the tr command with the pipe. The tr command is a character translator. It has two parameters in out case, a double quote and a space. It simply reads all the input then passes it as output converting every occurrence of the double quote into a space.

That is how you generate the output in the format you require.



Does that explain it properly? I've never been a good teacher, so please feel free to complain or ask more questions about it.




Robin
Liverpool/Blackburn
UK