[bug-gawk] Computed regex and getline bug / issue

[Grail Dane]

Hello

As part of an exercise in displaying data from a file I have come across an issue which neither myself nor any of the

good people at linuquestions.org have been able to solve and believe it may be a bug within gawk.

Using the following data as an input file:

1 , 2

3 , 4

5 , 6

7 , 8

9 , 10

In case this does not display correctly, the format is - number space comma space number

Using the following basic gawk we are able to return data as follows:

$ awk '{print "|"$0"|"}' RS='[,\n]' file

|1 |

| 2|

|3 |

| 4|

|5 |

| 6|

|7 |

| 8|

|9 |

| 10|

Pipes included to simply show white space.

If we then use getline prior to our print we receive:

$ awk '{getline;print "|"$0"|"}' RS='[,\n]' file

| 2|

| 4|

| 6|

| 8|

| 10|

Which again is all fine, however, if we then extend the RS computed regex to allow for spaces, our original output is the same but minus the spaces:

$ awk '{print "|"$0"|"}' RS='[,\n ]+' file

|1|

|2|

|3|

|4|

|5|

|6|

|7|

|8|

|9|

|10|

Again, as expected.  Once we go back to our getline version where we expect to return every second record, we now see our 'bug':

$ awk '{getline;print "|"$0"|"}' RS='[,\n ]+' f2

|2|

|4|

|6|

|8|

|9|   <-- This should have been |10|

The thread for further discussion on this issue can be found here :- http://www.linuxquestions.org/questions/programming-9/peculiar-awk-behaviour-confusing-me-4175503599/

Please advise if you should require any further information?

Cheers

Grail