Grepping data using awk

Shell Programming and Scripting
1

Hello,

I have a data in file 1

2000000024776
2000000026979
2000000033355
2000000036309
2000000041291
2000000042679
2000000067221


and in file 2 its like this

2000000024776   16
2000000026979   16
2000000033355   16
2000000036309   16
2000000041291   16
2000000042679   16
2000000067221   16
2000000117968   13
2000000120830   14
2000000120897   13
2000000121192   14
2000000123529   17
2000000125318   17
2000000128635   8



output is 

2000000024776   16
2000000026979   16
2000000033355   16
2000000036309   16
2000000036309   16
2000000036309   16
2000000041291   16
2000000042679   16
2000000067221   16

I am searching for data of file file and printing it using below script but its slow

while read line1
do
echo "$line1"
a=`echo $line1|cut -c 1`
if [ $a -ge 0 ]
then
num=`echo "$line1"|cut -c 1-13`
echo "$num"
cat file3.csv |nawk -v "c=$num" '$1 ~ c' >> new_file.csv
fi
done < file4.csv
2

Just join two files:

join -1 1 -2 1 file2 file1
3

Another way:

awk 'NR==FNR { A[$1]++; next } $1 in A' file1 file2