mjhjmtu

I have a table as of below

fruits shopname 
Apple x1
orange x1
banana x2
Apple x3
orange x2
banana x3

I want to group all rows based on column 1 and replace the duplicates with empty space.

It will look like below.

fruits shopname 
Apple x1
 x3
banana x2
 x3
orange x1
 x2

I know we can remove duplicates with uniq command.
but here I want to group them and replace duplicates with empty space.

You need to read the file line by line, and build up a data structure that associates the fruit to a list of shop numbers. You can do this with awk's multidimensional arrays, or with GNU awk's array of arrays.

Then, after you have read the file, you will loop over the fruits, and for each fruit, print out a line for each shop.

I'd use perl for this, but the syntax for perl can be somewhat overwhelming.

perl -lane '
 if ($. == 1) print; next
 push @$shops$F[0], $F[1];
 END{
 for $fruit (sort lc $a cmp lc $b keys %shops) 
 $label = $fruit;
 for $shop (@$shops$fruit) 
 printf "%st%sn", $label, $shop;
 $label = "";
 
 
' file

I have used below method to achieve the same

for i in `awk 'print $1' y.txt| sort| uniq| tr "n" " "`; do awk -v i="$i" '$1 == i print $2' y.txt| sed "1s/.*/$it&/g"| sed '/^x/s/.*/t&/g';done| sed '1i fruits shopname '

output

fruits shopname 
Apple x1
 x3
banana x2
 x3
orange x1
 x2

Try:

sort -t $'t' <(tail -n+2 infile) |awk 'seen[$1]++ $1="" 1' OFS='t'
Apple x1
 x3
banana x2
 x3
orange x1
 x2

I don't understand why do you need empty fruits name, which you can simply query the data you need, everything other than result you can consider it's empty.

sort -t $'t' -uk1,1 <(tail -n+2 infile)
Apple x1
banana x2
orange x1

Another version using sed, but the first that creates an input file.

Make sure you disable your bash history expansion with set +H before running this

Code: (copy & paste into your shell)

# replace comma with tab to enable copy&paste from stackexchange,
# sort the table, write the file
cat <<EOF | tr ";" "t" |sort > fruits.txt
Apple;x1
orange;x1
banana;x2
Apple;x3
orange;x2
banana;x3
EOF

echo "BEFORE:"
cat fruits.txt

for fruit in $(cut -f1 fruits.txt|sort -u); do sed -i "/$fruit/!b;n;s/^w+//" fruits.txt; done

echo "RESULT:"
cat fruits.txt

Output:

BEFORE:
Apple x1
Apple x3
banana x2
banana x3
orange x1
orange x2
RESULT:
Apple x1
 x3
banana x2
 x3
orange x1
 x2