I'm trying to follow the instruction https://doc.dovecot.org/2.3/configuration_manual/howto/antispam_with_sie ve/ to setup IMAPSieve

I cannot find any info on what sieve_pipe_bin_dir should point to. Any references I have found to this point to the old wiki.

My current spam learning sieve scripts are in file:/home/vmail/sieve/global/ Should sieve_pipe_bin_dir point to this?

It has been a while since I was doing this sieve, but you can point them to your own locations

sieve_execute_bin_dir = /usr/lib64/dovecot/sieve-execute sieve_filter_bin_dir = /usr/lib64/dovecot/sieve-filter sieve_pipe_bin_dir = /usr/lib64/dovecot/sieve-pipe

Just make sure you put your binary in the correct dir. so if you use in your script 'filter "xxxxx"', xxxx is in the filter dir.