paste command leaves empty rows - awk

Question

Hi I was trying to paste multiple files (each with a single column but different number of rows) together.
paste file1.txt file2.txt paste3.txt ... paste100 > out.txt
input file 1:
A
B
C
input file 2:
D
E
input file 3:
F
G
H
I
J
output:
A D F
B E G
C H
I
J
When I cut column 2 (cut -f2) from out.txt file , it gives column 2 with 3 empty rows (probably because column has 5 rows so to match to column 3, it created 2 extra empty rows). Same goes for column 1 (less out.txt | cut -f1) which gives 2 empty rows. Any ideas why does it show the empty rows?
less out.txt | cut -f1
A
B
C
empty cell
empty cell
less out.txt | cut -f2
D
E
empty cell
empty cell
empty cell
I was expecting to see-
column 1
A
B
C
column 2
D
E

Answer 1

None of the rows are empty, some of them just don't have all of the fields populated but they do still have the field separators (tabs) that paste output. cut has no way of knowing that you don't want the empty fields printed.
Try:
awk -v f=1 -F'\t' '$f!=""{print $f}' file
awk -v f=2 -F'\t' '$f!=""{print $f}' file
instead.

Answer 2

We can use awk to do the replacement of blank fields with the empty cell value. Here I have used '|' as a delimiter to make the replacement operation flawless. The delimiter can again be converted to tabs or spaces if wanted with tr -s '|' '\t'.
$ paste -d '|' {a,b,c}.txt|awk 'BEGIN{FS=OFS="|"} {print ($1=="" ? "empty cell" : $1), ($2=="" ? "empty cell" : $2), ($3=="" ? "empty cell" : $3)}'
Output with pipe delimited.
A|D|F
B|E|G
C|empty cell|H
empty cell|empty cell|I
empty cell|empty cell|J
Output with tab delimited.
A D F
B E G
C empty cell H
empty cell empty cell I
empty cell empty cell J