single space as field separator with awk

Question

I am dealing with a file where fields are separated by a single space.

awk interprets the FS " " as "one or more whitespace", which misreads my file when one of the fields is empty.

I tried using "a space not followed by a space"( " (?! )" ) as FS but awk does not support negative lookahead. Simple google queries like "single space field separator awk" only sent me to the manual page explaining the special treatment of FS=" ". I must have missed the relevant manual page...

How can I use a single space as field separator with awk?

Answer 1

this should work

$ echo 'a    b' | awk -F'[ ]' '{print NF}'
5

where as, this treats all contiguous white space as one.

$ echo 'a    b' | awk -F' ' '{print NF}'
2

based on the comment, it need special consideration, empty string or white space as field value are very different things probably not a good match for a white space separated content.

I would suggest preprocessing with cut and changing the delimiters, for example

$ echo 'a    b' | cut -d' ' -f1,3,5 --output-delimiter=,
a,,b