How can I make my Mac accept a user password of less then 4 characters?
I found this not so easy solution on web, that works quickly instead of necessity to do it by Server application from apple.

In Terminal:

pwpolicy getaccountpolicies &gt; temp.xml
nano temp.xml


Now remove text prior to first &lt;xml tag and replace

&lt;string&gt;policyAttributePassword matches '^$|.{4,}+'&lt;/string&gt;


to

&lt;string&gt;policyAttributePassword matches '^$|.{1,}+'&lt;/string&gt;


then save file (Ctrl-O), exit (Ctrl-X) and run

sudo pwpolicy setaccountpolicies temp.xml


to install the updated policy.