Tab separated values in awk
AwkAwk Problem Overview
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 "," $9 "}' >> /pdump/temp.txt
Awk Solutions
Solution 1 - Awk
You need to set the OFS variable (output field separator) to be a tab:
echo "$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)
Solution 2 - Awk
Make sure they're really tabs! In bash, you can insert a tab using C-v TAB
$ echo "LOAD_SETTLED LOAD_INIT 2011-01-13 03:50:01" | awk -F$'\t' '{print $1}'
LOAD_SETTLED
Solution 3 - Awk
You can set the Field Separator:
... | awk 'BEGIN {FS="\t"}; {print $1}'
Excellent read:
https://docs.freebsd.org/info/gawk/gawk.info.Field_Separators.html
Solution 4 - Awk
Use:
awk -v FS='\t' -v OFS='\t' ...
Example from one of my scripts.
I use the FS and OFS variables to manipulate BIND zone files, which are tab delimited:
awk -v FS='\t' -v OFS='\t' \
-v record_type=$record_type \
-v hostname=$hostname \
-v ip_address=$ip_address '
$1==hostname && $3==record_type {$4=ip_address}
{print}
' $zone_file > $temp
This is a clean and easy to read way to do this.
Solution 5 - Awk
echo "LOAD_SETTLED LOAD_INIT 2011-01-13 03:50:01" | awk -v var="test" 'BEGIN { FS = "[ \t]+" } ; { print $1 "\t" var "\t" $3 }'
Solution 6 - Awk
Should this not work?
echo "LOAD_SETTLED LOAD_INIT 2011-01-13 03:50:01" | awk '{print $1}'