LFCS Exam Preparations

1. Essential Commands - 25%
1. cut
2. diff
3. awk
4. sort
5. sed
6. cmp
7. find -exec cp {} <directory> \;
8. vi
2. Operation of Running Systems - 20%
1. systemctl --list-units --type=service
3. User & Group Management - 10%
1. chmod
2. chown
3. usrquota, grpquota
4. ulimit
4. Networking - 12%
1. netstat
2. ss
3. ifconfig
4. wget
5. curl
6. lsof
7. nmcli
1. gateway
2. ip
3. dns
5. Service Configuration - 20%
1. ssh
2. selinux
6. Storage Management - 13%
1. lvm
1. lvcreate -L 1G -m 2 -n lvol01 vg01
2. lvscan
2. vgs
1. vgcreate
2. vgs
3. vgdisplay
4. vgchange
3. pvs

How to Prepare

Essential Commands domain might appears more frequently then others. For this domain you will have to:

• Archive, backup, compress and uncompress files using tar (along with gz/bz/xz)
• Searching files (using find, a lot of it in different levels)
• Compare and manipulate file content (using diff for example)
• Input-output redirection (>,>>,<<,<,|,2&1 etc.)
• Create, manage hard and soft links
• List, set, and change standard file permissions (including SUID/SGID, sticky bit)
• Create, delete, copy, and move files and directories
• Using all other common console utilities
• Read and use system documentation (man, apropos commands are your friends during exam)

Next is Operation of Running Systems. For this domain you should know how to:

• Locate and analyse system log files and manipulate it
• Limit the number of user processes for a specific account or group
• Install/update packages, get information about installed packages (depends on your distribution)
• Schedule tasks to run at a set date and time (using cron)
• Use scripting to automate system maintenance tasks
• Diagnose and manage processes (find process ID for example)

For User and Group Management domain you should know how to:

• Create, delete, and modify local user accounts
• Create, delete, and modify local groups and group memberships
• Configure startup files (read about /etc/skel)
• Manage user privileges
• Configure custom environment paths for user

For Networking domain you should know how to:

• Configure networking and hostname resolution (using hostnamectl)
• Configure network services to start automatically at boot (using systemctl, read about systemd-networkd/systemd-resolved)
• Start, stop, and check the status of network services
• Implement packet filtering (iptables, no firewalld since it’s not related to RHEL)
• Manipulate /etc/hosts file

For Service Configuration domain you should know how to:

• Manage and configure containers (you’d better know all common and widely used docker commands for this exam)
• Manage Virtual Machines (using virsh)
• Configure SSH servers and clients
• Configure an HTTP server https://www.digitalocean.com/community/tutorials/how-to-install-the-apache-web-server-on-centos-7
• Restrict access to a web page
• Configure a database server

And the last one is Storage Management. For this domain you should know how to:

1. List, create, delete, and modify physical storage partitions, including GPT (using fdisk, gdisk utilities)
1. https://www.certdepot.net/rhel7-create-delete-partitions/
2. Manage and configure LVM partitions
1. https://www.thegeekdiary.com/redhat-centos-a-beginners-guide-to-lvm-logical-volume-manager/
3. Create and manage software RAID (using mdadm)
1. https://www.ducea.com/2009/03/08/mdadm-cheat-sheet/
4. Mount file systems during boot (using systemctl mount target)
5. Configure user and group disk quotas for filesystem
1. https://www.linuxtechi.com/enable-user-group-disk-quota-on-centos-7-rhel-7/vi 
2. https://developpaper.com/install-quota-in-centos-system-to-manage-disk-quota/dquivoi 
6. Configure and manage swap partitions or files
1. https://linuxize.com/post/how-to-add-swap-space-on-centos-7/
7. Be familiar with storage encryption (using LUKS)

I must say that the last domain requires additional configurations to prepare. In my case I used Oracle VirtualBox to manipulate storage devices and partitions using CentOS Linux 7.+ image.
Also I found it useful (as an option) to use any Cloud provider (like DigitalOcean, for example) to use it for separate VM and additional volumes if you don’t have enough resources on your laptop or PC. You can also use it as test place for LVM configuration.

Some advice:

• During the exam you might be asked to login via SSH into another VM, don’t forget to log out when you’re done. It will take extra time before you realize you’re doing something wrong (like me did such mistake in a rush). Be more attentive.
• Always use man, apropos if you forget something. It can help you to find necessary command options.
• Don’t waste your time on one task if you stuck during exam, go ahead and solve others. You will have time to return, if not — you will resolve more then this one anyway.
• Don’t try to ask proctor to help you or walk you through. It’s useless. Everything might be found by yourself using man or — help command.