UNIX for Dummies Questions & Answers

Dear all,
I have tried the following 2 lines

xargs -t -i -exec grep -i -w {} file_1 >>test < file_2

cat -s file_2| xargs -t -i -exec grep -i -w {} file_1 >> test

They were meant to search for the contents of file_2 in file_1 and write the respective lines of file_1 into file "test" . But instead it writes a standard error output
grep -i -w "string1" File_1
grep -i -w "string2" File_1
grep -i -w "string3" File_1
and creates an empty file "test"
Any ideas why this doesn't work?
I f I copy each of the above lines from the standard error output
they work and produce the expected result
Your help is very much appreciated

Thanks
Bruno

I didn't check the lines but basically you can have this easier with

Code:

grep -vf file_2 file_1 > test

Hi Zaxxon,
thanks for the quick reply. Unfortunately that doesn' work. I think the problem is that the info I am looking for looks like this

file_2
TAG_1
TAG_2
TAG_4
TAG_6
...

file_1
TAG_1 Boston
TAG_2 New York
TAG_3 Munich
TAG_4 London
TAG_5 Paris
TAG_6 Madrid
TAG_7 Lisbon
...
Your command line puts the whole content of file_1 into test and not only
TAG_1 Boston
TAG_2 New York
TAG_4 London
TAG_6 Madrid

Ah, you want grep to hunt for multiple things. Giving grep multiple parameters won't make it hunt for multiple strings, it will take every parameter after the first one as a filename to search in. You need to use egrep, and assemble the tags you want to look for into a single string like

Code:

egrep 'TAG_1|TAG_2|TAG_3|TAG_4' file > output

Hi Corona688,
thanks for the reply. Unfortunately that doesn' work either. The result is the same as the one I get when I use Zaxxon suggestion.
file_2
TAG_1
TAG_2
TAG_4
TAG_6
...

file_1
TAG_1 Boston
TAG_2 New York
TAG_3 Munich
TAG_4 London
TAG_5 Paris
TAG_6 Madrid
TAG_7 Lisbon
...
Your command line puts the whole content of file_1 into test and not only
TAG_1 Boston
TAG_2 New York
TAG_4 London
TAG_6 Madrid

Thanks for trying

Bruno

wouldn't

Code:

fgrep -f file2 file1 > test

Do what you want?

Dear reborg,
that doesn't work it just produces an empty file "test".

Thanks for trying

Bruno