Shell Programming and Scripting

cat infile.txt
0  AJ2312  310  3  34   ABT
0  BG231 310 2 55 ABG
1  GG342 305 5 77 AGG
2  HJ1231 404 6 99 ZTJ
...

cat reference.txt
0 LIB123
1 LIB223
2 LIB333
...

cat results.txt
LIB123  AJ2312  310  3  34   ABT
LIB123  BG231 310 2 55 ABG
LIB223  GG342 305 5 77 AGG
LIB333  HJ1231 404 6 99 ZTJ

for SEQN in 1
do
    LIB=`grep "^>${SEQN}" -w reference.txt | awk '{print $2}'`
    echo ${LIB}
    sed 's/'"$SEQN"'/'"$LIB"'/' infile.txt >> results.txt
done

join infile.txt reference.txt

awk 'NR==FNR{A[$1]=$2;next}{sub($1,A[$1]);print}' reference.txt infile.txt

A[0]=LIB123, A[1]=LIB223, A[2]=LIB333

{A[$1]=$2;next}

{sub($1,A[$1]);print}