Off topic:How to repeat a row for each value of its corresponding column

Question

[ak93sharma]

hello folks , i am not expert in programming , I want to repeat a row for all its corresponding values any help

my input file is like this

pos COL1    COL2    COL3
18691441    C   A   G
18691572    G   C   G
18691620    A   T   G
18691716    C   G   C

i want output like this

pos COL1    
18691441    C   
18691441    A   
18691441    G   
18691572    G   
18691572    C   
18691572    G   
18691620    A   
18691620    T   
18691620    G   
18691716    C   
18691716    G   
18691716    C

i am trying to repeat a row but it simply makes them duplicate , i am using

while read line; do for i in {1..3}; do echo "$line"; done; done < real2.txt

and gives output:

pos COL1    COL2    COL3
18691441    C   A   G
18691441    C   A   G
18691441    C   A   G
18691572    G   C   G
18691572    G   C   G
18691572    G   C   G
18691620    A   T   G
18691620    A   T   G
18691620    A   T   G
18691716    C   G   C
18691716    C   G   C
18691716    C   G   C

then i extracted pos from input 1.txt file and make 1_pos.txt and write something like this:

 pos
18691441
18691572
18691620
18691716
for i in `cat 1_post.txt`;
do
x=$(grep -i "^$i" 1.txt | awk 'FNR == 1 {print $1"\t"$2}' ) ;
y=$(grep -i "^$i" 1.txt | awk 'FNR == 1 {print $1"\t"$3}' ) ;
z=$(grep -i "^$i" 1.txt | awk 'FNR == 1 {print $1"\t"$4}' ) ;
echo -e "$x""\n""$y""\n""$z";
done

this gives me output, without col information:

18691441    C
18691441    A
18691441    G
18691572    G
18691572    C
18691572    G
18691620    A
18691620    T
18691620    G
18691716    C
18691716    G
18691716    C