----> To check AIX log files:

AIX error log (read with the errpt command)

/var/adm/wtmp account file (read with the last command)

/var/adm/pacct account files (read with the lastcomm command)

AIX console log (read with the alog -t console -o command)

su log file (read with cat /var/adm/sulog)  

Shell history file (read with the fc command)

/etc/shutdown.log file (read with cat /etc/shutdown.log)