UNIX for Dummies Questions & Answers

for a in {1..32..1};do awk '{print$a}' file1.txt|while read line;do grep $line file2.txt;done > file3.txt;done

[user@host2: /tmp] cat 1.txt
aaa bbb ccc eee
[user@host2: /tmp] cat 2.txt
aaa bbbb
cccc
dddd
eeee
ffff
gggg
hhhh cccc
[user@host2: /tmp] grep -f <(tr ' ' '\n' <1.txt) 2.txt
aaa bbbb
cccc
eeee
hhhh cccc

grep -f <(tr ' ' '\n' <file1.txt) file2.txt > file3.txt

A    G    K    N    Q    T    W    
B   H    L    O    R    U    X    
C    I   M    P    S    V    Y   
D    J                        
E                            
F

A p1 p2 p3
B s1 s2 s3 s4 
E a1 a2 
P f1 f2
J d1 d2 d3 d4 d5

A
B
C
D
E
F

A p1 p2 p3
B s1 s2 s3 s4 
E a1 a2

G
H
I
J

J d1 d2 d3 d4 d5