Shell Programming and Scripting

Code:

awk '
NR==FNR{a[substr($0,1,11)];next}    # Create an array of the key (position 1-11) in file2
substr($0,21,11) in a{print}        # If position 21-31 of file1 exist in array print the record
' file2 file1

This link gives an explanation how to deal with errors in awk:

Debugging (sed & awk, Second Edition)

Regards

Another point of cleverness to note is "NR==FNR" which is true while processing the first line on the command line. Both are incremented when a new line is read, but FNR gets reset to zero when the file changes, while NR grows forever. And the "next" on that line means the following line of the script doesn't get executed while the condition is true; it causes awk to read the next line and start over.

Hi,

If I want to add one more condition to the below while comparing.. can I modify as below =>

Old code
========
awk '
NR==FNR{a[substr($0,1,11)];next} # Create an array of the key (position 1-11) in file2
substr($0,21,11) in a{print} # If position 21-31 of file1 exist in array print the record
' file2 file1

New code
========
awk '
NR==FNR{a[substr($0,1,11)];next} # Create an array of the key (position 1-11) in file2
substr($0,21,11) | substr($0,41,11)in a{print} # If position (21-31) or (41 -51) of file1 exist in array print the record
' file2 file1


Many thanks in advance.

The syntax for specifying multiple conditions is a bit more explicit and cumbersome.

Code:

(substr($0,21,11) in a || substr($0,41,11) in a) { print }

Note also that the logical "or" operator is a double pipe, not single.