[kwlug-disc] bash question tab separated values

[Robert P. J. Day]

On Thu, 5 Nov 2009, Khalid Baheyeldin wrote:

>
> On Thu, Nov 5, 2009 at 2:46 PM, Richard Weait <richard at weait.com> wrote:
>       I'm reading lines from a tab-separated-value text file.  Ten values
>       per line.  I'd like to load them into ten variables for further
>       processing, then output.
>
>       It ain't working for me.  Looks like the tabs are being silently
>       dropped then my cut -f3, for example, returns the complete line.
>
>       Some fields include spaces, so I'd rather continue to split on
>       tabs.
>       How do I keep the tabs?  How should I be reading these lines?
>
>
> Can you process in awk?
>
> If so, then just use:
>
> awk -F"\t" '{print $1; ... something else; }' yourfile.txt
>
> If you still insist on doing it in shell, then do this:
>
> exec 3>&1 < file.txt
> while true
> do
>   read LINE
>   if [ "$?" != 0 ]; then  # It is an End Of File condition
>     break
>   fi
>
>   FIELD0=`echo "$LINE" | awk -F"\t" '{print $1}'`
>   FIELD1=`echo "$LINE" | awk -F"\t" '{print $2}'`
>   FIELD2=`echo "$LINE" | awk -F"\t" '{print $2}'`
>
>   echo $FIELD0
>   echo $FIELD2
> done
> exec <&3 3<&-

  can't you just set the internal field separator before reading in
the file in a bash loop:

  IFS="<TAB>"
  while read v1 v2 v3 ...etc... v10 ; do
    ... whatever with v1 v2 v3 ...
  done < inputfile

  the proper way to set the IFS would be (from experience), typing the
first quote, then a ^v, followed by pressing the TAB key, then
finishing off with the closing quote.  the ^v means "take the next
character absolutely literally."

  i just tested that and it seems to work.

rday
--

========================================================================
Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
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