awk prints unwanted new lines

Shell Programming and Scripting
1

Hello,

I need a little help with the following:

I'm using AWK to read input from a comma-seperated value file, and only printing certain fields like so:

awk -F "," '{print $1,$3,$6}' /list.csv | tail -1

Which outputs the following:

server1 APPID OS

I run into a problem when I add it to a for loop:

LIST=list.csv
for i in $(awk -F "," '{print $1,$3,$6}' ${LIST} | tail -1)
  do
    echo ${i}
done

The output is as follows:

server1
APPID
OS

How can I fix this so that the output is on one line instead of three different lines?

Thanks in advance.

2

Hello LinuxRacr,

Could you please let us know what you are trying to do here. I think we can get the desiered output within awk itself. Kindly let us know the complete requirement. Using awk wihin a loop means each time calling it an may be unnecessarily increasing the execution time for it.
May be we can do things easily within awk itself.

Thanks,
R. Singh

3

Your for loop construct reads like this:

for i in server1 APPID OS
  do
    echo ${i}
done

which it will do:

echo server1
echo APPID
echo OS

As RavinderSingh says, tell us what you want to get done ...

4

The csv file is holding data which will be parsed to perform functions such as creating lists, or running system checks based on the info.

Here is a little more of the script:

LIST=list.csv
OUTDIR=/prod/lists
for i in $(awk -F "," '{print $1,$3,$6}' ${LIST} | tail -1)
  do
    echo ${i}
    SERVER=$(echo "${i}" | awk '{printf $1}')
    APPID=$(echo "${i}" | awk '{printf $2}')
    OS=$(echo "${i}" | awk '{printf $3}')
    APPDIR="${OUTDIR}/${APPID}"
    mkdir -p ${APPDIR}
    echo "${SERVER}" >> ${APPDIR}/${OS}.list
done
5

Having seen my previous post, you certainly are able to identify the errors in your script...

6

Use a while loop:

tail -1 "$LIST" | while IFS=, read SERVER APPID OS APPDIR junk; do
  echo $SERVER
  : ...
done

A for loop will iterate its input one word at a time.

If you don't just want the last line (you did use tail -1 ), then:

while IFS=, read SERVER APPID OS APPDIR junk; do
  echo $SERVER
  : ...
done < "$LIST"
1 Like
7

RudiC,

Each line will be different in the csv file being used for input. That is why I am trying to use AWK. Am I missing something?

8

Hello LinuxRacr,

For simple printing following may help (As per post#1).

 awk 'END{print "SERVER= " $1 OFS "APPID= "$3 OFS "OS= "$6}' Input_file

For getting values into variables we can use following.

SERVER=`awk 'END{print $1}' Input_file`
APPID=`awk 'END{print $3}' Input_file`
OS=`awk 'END{print $6}' Input_file`

After that you try to write the script and do the further more operations as you have shown us to create directory etc as per your requirements.
Hope this helps.

Thanks,
R. Singh

9

Great Scott! I believe my issue is solved. IFS did the trick.