I have been trying to do this for sometime now but I have not been able to do it. Say I have a file named 'John', with content like this:
and I have other files with each file listed from 1- 50000 like this:
file A
I have many of such files A but with different filenames. These are all in the same directory.
I want to use file named "john" to compare field 1 in file A and all the other files like this: wherever you have 6 in filed 1 file A print entire line, then take 10 from file John look for 10 in file A and print line. Output will look like this:
This comparism is then done for each other file
Thanks all

is this homework ? what have you tried so far ? where are you stuck ?

look into the -f and -w parameters of the grep command.