How to use the flag -p of BSD split? Manual

-p pattern
         The file is split whenever an input line matches pattern,
         which is interpreted as an extended regular expression.  The
         matching line will be the first line of the next output file.
         This option is incompatible with the -b and -l options.


Code

seq -w 1 1 10 | gsed ':a;N;$!ba;s/\n//g' | split -p '060'


which makes a sequence from 1 to 10, removes empty lines to have a megastring and then splits at 060 into two files unsuccessfully giving split: invalid option -- 'p'. 

Command seq -w 1 1 10 | awk -F'060' '{print "field1: "$1 "\nfield2: 060"$2}' in comment gives 


  field1: 01 field2: 060 field1: 02 field2: 060 field1: 03 field2: 060 field1: 04 field2: 060 field1: 05 field2: 060 field1: 06 field2: 060 field1: 07 field2: 060 field1: 08 field2: 060 field1: 09 field2: 060 field1: 10 field2: 060


which is not what I want. 
I want to split the file at the mark 060 to two files. You can include 060 to either file. 

How can you use the flag -p in BSD Split in OSX?
The issue is caused by BSD split being later in your path than the GNU split (which doesn't support the -p option). If you do an echo $PATH you should see this - /usr/local/opt/coreutils/libexec/gnubin will be before /usr/bin in the output.

To call BSD split directly, use the full path - pipe to /usr/bin/split instead of split.

Your original command will then become:


seq -w 1 1 10 | gsed ':a;N;$!ba;s/\n//g' | split -p '060'