storing columns in different variables

[Anand_30]

Hi,

Please find attached a file which has 2 columns. I need to store the column values in 2 different variables and use them in a SHELL script. I have an excutable which takes the coulmn values as parameters.

Thanks,
Andy

[A. Clay Stephenson · Accepted solution]

Trivially simple:

MYFILE=myfile.txt

cat ${MYFILE} | while read A B
do
echo "A = \"${A}\" B = \"${B}\""
done

[Chris Vail]

Clay's script is, as he said, trivially simple. Its is limited to parsing the table from the beginning to the end. But what if you wanted to start at the end, and work up to the beginning? Here's a (probably needlessly) complex way to do this:

#!/usr/bin/ksh
LENGTH=`wc -l $FILE|awk '{ print $1 }'`
while test "$LENGTH" -ge "1"
do
LINE=`head -"$LENGTH" $FILE|tail -1`
A=`echo $LINE|awk '{ print $1 }'`
B=`echo $LINE|awk '{ print $2 }'`
(( LENGTH = "$LENGTH" - "1" ))
done

Another advantage (if there is one) is that not every version of Unix has the read command. But every one that I've ever seen has head, tail, and awk. Some versions (System V derivations, like old SCO) don't have wc either. If so, use
LENGTH=`pr -n -t $FILE|tail -1|awk '{ print $1 }'`
instead of the previous LENGTH statement. This uses up a lot more clock cycles than Clays script, but is portable across every version of Unix that I've ever seen. Its handy for log files.




Chris

[john korterman]

Hi,
this will probably also work:

# A=$(cut -f1 infile)
# B=$(cut -f2 infile1)

regards,
John K.