I am a part time user of Posix. So, if you are looking for the bare minimum you are likely at the right place. My development platform is a Windows laptop. My production server is a VPS running centos.
I put this page together as these are not command lines I run all the time. Having this page saves me the trouble of having to google for an example as I just do not do many of them enough to remember them off the top of my head.
I typically use WHM for a number of these functions, but I must confess preferring the command line.
/etc/init.d/httpd restart
/etc/init.d/sshd restart
/etc/init.d/cpanel restart
Note: Qualify the path as far as you know
find /home/public_html -name filename.txt -print
cat /etc/group | cut -d":" -f1
cat /etc/passwd | cut -d":" -f1
php.ini: /usr/local/lib
httpd.conf: /usr/local/apache/conf
Apache logs: /usr/local/apache/logs
Apache Php Config: /usr/local/apache/conf/php.conf
Apache error doc config: /usr/local/apache/conf/includes/errordocument.conf