Question

How do I select the first column from the TAB separated string?

# echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk -F'\t' '{print $1}'

The above will return the entire line and not just “LOAD_SETTLED” as expected.

Update:

I need to change the third column in the tab separated values.
The following does not work.

echo $line | awk 'BEGIN { -v var="$mycol_new" FS = "[ \t]+" } ; { print $1 $2 var $4 $5 $6 $7 $8 $9 }' >> /pdump/temp.txt

This however works as expected if the separator is comma instead of tab.

echo $line | awk -v var="$mycol_new" -F'\t' '{print $1 "," $2 "," var "," $4 "," $5 "," $6 "," $7 "," $8 "," $9 "}' >> /pdump/temp.txt

Answer 1

You need to set the OFS variable (output field separator) to be a tab:

echo "$line" | 
awk -v var="$mycol_new" -F'\t' 'BEGIN {OFS = FS} {$3 = var; print}'

(make sure you quote the $line variable in the echo statement)