Thanks c62ap90, that's cos I bloopered it. I'll update the original as well to avoid the confusion.
Should be:
OPTION COPY
OMIT COND=(1,5,SS,EQ,C' ')
//SORTIN DD *
12345
1 345
123 5
1234
12 5
2345
Output is:
The SS is a "field type". Here it will find one (or more) blanks in positions 1,5.
Another use of SS is to test the same field for multiple values, which can simplify things by removing an OR or two.
OPTION COPY
OMIT COND=(1,5,SS,EQ,C'12345,1 345, 2345')
//SORTIN DD *
12345
1 345
123 5
1234
12 5
2345
Output is: