Shell Programming and Scripting

Hi, I think it might be too advanced for me to understand? I'm not getting anything out of the man page for grep using -f

If your grep version supports the -f option:

Code:

grep -f file1 file2

Otherwise with awk:

Code:

nawk 'NR==FNR{a[$0]; next}$1 in a' file1 file2

Using
nawk 'NR==FNR{a[$0]; next}$1 in a' file1 file2 > test.txt

Dosnt seem to do the desired thing..

file1 is a little group of ID's i have which i need to get hold of their email associated to their ID. (926 lines/entries/users)
file2 is the complete list holding all ID's with their email address. (1045 lines/entries/users)

When i use the command, it creates a file containing 842 (lines/entries/users) where ID AND Email is listed.

I only need to get their Email address from their ID if theres a match and create a output file that only contains the emails that were a match.

Best regards

With the given sample files I get:

Code:

$ cat file1
451245
451288
136588
784522
$ cat file2
123888 xc@xc.com
451245 a@a.com
122112 adsadas@asd.com
451288 b@b.com
136588 c@c.com
784522 d@d.com
$ awk 'NR==FNR{a[$0]; next}$1 in a' file1 file2
451245 a@a.com
451288 b@b.com
136588 c@c.com
784522 d@d.com
$

Am I missing something?

IMO franklin's suggestion just needs a print $2 action. Plus I would tend to use $1 instead of $0 in the first part to avoid possible mismatches due to spurious spacing...

Code:

awk 'NR==FNR{a[$1]; next}$1 in a{print $2}' file1 file2

Thanks guys, I've got it working now :-)

Lets say i now need to search for missing entries between two files. I would like to print $1 from file1 if the number isnt found in file2?

file1(total)
1
2
3
4
5
6

file2 (partial)
1
2
3


output(numbers missing)
4
5
6


Thanks