Join two txt files

Question

Using Linux: *.txt files

file1

HOUSAM000001189870 1012212222011212100020102102112011002200111112012220110 ....... 
HOUSAM000001213135 2012012000120120102010201002102111200122201100222201102 .......
HOUSAM000001237057 0012011222010210120120122210000101112000222210102010201 .......
HOUSAM000001239242 2210120111010010100100022001111000010220010102010201022 .......

file2

HOUSAM000001189870     
HOUSAM000001237057

Output file

HOUSAM000001189870 1012212222011212100020102102112011002200111112012220110 .......
HOUSAM000001237057 0012011222010210120120122210000101112000222210102010201 .......

Answer 1

grep -F -f file2 file1 > file3

If you need to match only the first column and you can change the patterns file you can add ^ to the front of each line and treat that file as regex (remove the first -F). So...

file2:

^4046
^4050
^4047

Then:

grep -f file2 file1 > file3

If you can't change the patterns file or if it is generated outside of your control then Serge's answer is the best one.

Answer 2

Use the join command in conjunction with sort :

$ join <(sort 1.txt) <(sort 2.txt)
4046 200344
4047 200122
4050 200001

Answer 3

另一种选择：

sed 's/^/^/;s/$/[[:space:]]' file2 | grep -f - file1 > file3

Answer 4

One way using awk :

 awk 'FNR==NR { array[$1]=$2; next } $1 in array { print $1, array[$1] }' file1.txt file2.txt

Results:

4046 200344
4050 200001
4047 200122

Edit: using real data:

awk 'FNR==NR { array[$1]=$0; next } $1 in array { print array[$1] }' file1.txt file2.txt

Results:

HOUSAM000001189870 1012212222011212100020102102112011002200111112012220110 ....... 
HOUSAM000001237057 0012011222010210120120122210000101112000222210102010201 .......