How to add columns to a file based on matched column and maintain the order of lines using awk

Question

How can I match a column from a file to next file and append the columns if present using awk.

File 1:

T36
T200
T77
T99
T100
T101
T110

File2:

T36 aa  123
T36 aa  456
T200 cc 789
T99 aa  1011
T77 bb  1213
T77 bb  1415
T100 xx 1617

Desired output:

T36 aa  123
T36 aa  456
T200    cc  789
T77 bb  1213
T77 bb  1415
T99 aa  1011
T100    xx  1617
T101
T110

In my output file I want to get the order of file 1 and also print the lines that are not present in file 2.

So far I have done this but it is printing only the matched columns not all.

awk 'NR == FNR { x[$1]=$1; next} { print x[$1], $0 }' file1 file2

Please Help!

Asked By: ambika

||

Answer 1

awk 'f==2 {map[$1] = ($1 in map) ? map[$1] ORS $0 : $0} 
     f==1 {print (($1 in map)? map[$1] : $1)}
' f=2 file2 f=1 file1

or the same using the FNR==NR idiom:

awk 'FNR==NR {map[$1] = ($1 in map) ? map[$1] ORS $0 : $0; next} 
     {print (($1 in map)? map[$1] : $1)}
' file2 file1

Output:

T36 aa  123
T36 aa  456
T200 cc 789
T77 bb  1213
T77 bb  1415
T99 aa  1011
T100 xx 1617
T101
T110

Answered By: thanasisp