RHCSA Exam Study Guide with Complete Solutions

RHCSA Exam Study Guide with Complete Solutions Repeat last command - Answer️️ -!! Repeat last argument in current command - Answer️️ -!$ Kernel log message command - Answer️️ -dmesg File usage - Answer️️ -du -hsx h - human, s - summarize, x - single fs Umount a busy drive - Answer️️ -kill -9 'lsof +D /mnt/cdrom' (list open files, +D=directory and contents) Compare file contents - Answer️️ -diff Search for all gzip files, not dirs - Answer️️ -find -type f -name *.gz Command to tell crond what to do - Answer️️ -crontab crontab order - Answer️️ -Min, hour, date, month, day, command Show what's in crond - Answer️️ -crontab -l Turn on firewall for run levels 2-5 - Answer️️ -chkconfig iptables on Check if cmd is running - Answer️️ -service cmd status =old systemctl status cmd =new Set tasks for crond - Answer️️ -crontab -e ©SOPHIABENNET@2024/2025 Tuesday, August 20, 2024 10:21 AM 2 e = edit Mail location - Answer️️ -/var/spool/mail Command to check messages - Answer️️ -mail Check cmd run level schedule - Answer️️ -chkconfig --list cmd Print a file's number of lines - Answer️️ -wc -I file l=line User account commands - Answer️️ -useradd, userdel, usermod usermod switches - Answer️️ -G second group, g main group, u user ID num, d home, s shell Set user password - Answer️️ -passwd --stdin user Delete user account AND home dir - Answer️️ -userdel -r r = remove Force user password change - Answer️️ -chage -d 0 user change + age -d = last day Group-file field categories - Answer️️ -/etc/group gname:x:gid:users User account lock cmd - Answer️️ -usermod -L or -U usr U = unlock ©SOPHIABENNET@2024/2025 Tuesday, August 20, 2024 10:21 AM 3 Check if user account is locked - Answer️️ -less /etc/passwd user:! means locked :!! means no password set Show password parameters - Answer️️ -chage -l login l = list Set password max life - Answer️️ -chage -M # of days Firewall settings GUI - Answer️️ -system-config-firewall Scan for open ports - Answer️️ -netstat -tulpn (as root) nmap 192.168.1.10 tu=tcp/udp, l=only listening, p=sh pid, n=numeric address Yum repo location - Answer️️ -/etc/.d Turn cmd on for important run levels - Answer️️ -chkconfig cmd on cmd to see if crond is running - Answer️️ -ps -ef | grep crond e=every process, f=ASCII process hierarchy or service crond status =old systemctl status crond =new start crond - Answer️️ -service crond start =old ©SOPHIABENNET@2024/2025 Tuesday, August 20, 2024 10:21 AM 4 systemctl start crond =new turn cmd on for important run levels - Answer️️ -chkconfig cmd on check what levels cmd is set to run at - Answer️️ -chkconfig --list cmd cmd to set instructions for crond - Answer️️ -crontab -e script comment symbol - Answer️️ -# crontab format - Answer️️ -min hr date month day command what day number is Sunday - Answer️️ -zero cmd to get crontab help - Answer️️ -man 5 crontab cmd to view email - Answer️️ -mail where are emails stored - Answer️️ -/var/spool/mail show list of crond tasks - Answer️️ -crontab -l be careful of this when creating crond tasks - Answer️️ -the created task will run as the user you are logged in as cmd for disk usage - Answer️️ -du -hsx h - human, s - summarize, x - single fs cmd to find all open instances of cdrom - Answer️️ -lsof +D /dev/cdrom list open files, +D is for all instances and included files repeat previous argument - Answer️️ -!$ ©SOPHIABENNET@2024/2025 Tuesday, August 20, 2024 10:21 AM 5 cmd to repeat most recent command - Answer️️ -!! cmd to search in / for files named "root" (not dirs) - Answer️️ -find / - type f -name root What values do you set to staticly assign an IP to eth0 at system startup - Answer️️ -/etc/sysconfig/network-scripts/ifcfg-eth0 = ONBOOT=YES PROTO=none DNS server settings are stored here - Answer️️ -/etc/ remember this if you change any network config - Answer️️ -service network restart =old systemctl restart network =new what if no DNS server - Answer️️ -/etc/hosts is used as a sort of