--- tags: - linux - l1 - flashcard-deck - lpic-lfcs --- [Portal](../../../../library/portal/index.md) | **Level:** [L1: Foundations](../../../../library/portal/levels.md) | **Topics:** [LPIC / LFCS Exam](../../../../library/portal/topics.md) | **Domain:** Linux id category difficulty tags question answer source_path lpic-lfcs/001-lfcs-domains lpic-lfcs easy lpic, lfcs, exam What are the LFCS exam domains and their weights? Essential Commands: 25%\nOperation of Running Systems: 20%\nUser and Group Management: 15%\nNetworking: 15%\nStorage Management: 15%\nService Configuration: 10%\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/002-find-command lpic-lfcs medium lpic, lfcs, find How do you use find to locate files by name, size, time, and permissions? By name: find / -name "*.conf"\nBy size: find / -type f -size +100M\nBy time: find / -type f -mtime -7 (modified in last 7 days)\nBy owner: find / -user alice\nBy permission: find / -perm -4000 (SUID files)\nWith action: find /tmp -name "*.tmp" -delete\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/003-special-permissions lpic-lfcs medium lpic, lfcs, permissions What are setuid, setgid, and sticky bit? setuid (4xxx): binary runs as file owner, not the user running it. Example: /usr/bin/passwd\nsetgid (2xxx): on dirs, new files inherit the group. On binaries, runs as file group.\nsticky bit (1xxx): on dirs, only file owner can delete their files. Example: /tmp\nSet: chmod u+s (setuid), chmod g+s (setgid), chmod +t (sticky)\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/004-acls lpic-lfcs medium lpic, lfcs, permissions, acl How do you use POSIX ACLs for fine-grained file permissions? Set: setfacl -m u:alice:rwx file\nSet group: setfacl -m g:devs:rx directory\nView: getfacl file\nRemove: setfacl -x u:alice file\nRemove all: setfacl -b file\nACLs shown by + in ls -l output: -rw-r--r--+\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/005-io-redirection lpic-lfcs easy lpic, lfcs, shell What are the common I/O redirection operators in bash? > stdout to file (overwrite)\n>> stdout to file (append)\n2> stderr to file\n&> stdout + stderr to file\n| pipe stdout to next command\n< stdin from file\n2>&1 redirect stderr to stdout\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/006-systemd-targets lpic-lfcs medium lpic, lfcs, systemd How do you manage systemd targets (runlevels)? Check: systemctl get-default\nSet: sudo systemctl set-default multi-user.target\nSwitch now: sudo systemctl isolate rescue.target\nCommon targets: graphical.target (GUI), multi-user.target (CLI), rescue.target (single-user), emergency.target\nEquivalent to old runlevels 0-6.\n\nRemember: 0=halt, 1=single, 3=multi+net, 5=GUI, 6=reboot. "0=Off, 3=Server, 5=GUI, 6=Reboot." training/library/topics/lpic-lfcs/primer.md lpic-lfcs/007-journalctl lpic-lfcs medium lpic, lfcs, systemd, logging How do you use journalctl for log analysis? By service: journalctl -u nginx\nBy time: journalctl --since "1 hour ago"\nBy priority: journalctl -p err (emerg/alert/crit/err/warning/notice/info/debug)\nCurrent boot: journalctl -b\nPrevious boot: journalctl -b -1\nFollow: journalctl -u nginx -f\nDisk usage: journalctl --disk-usage\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/008-user-management lpic-lfcs easy lpic, lfcs, users How do you create and manage users on Linux? Create: useradd -m -s /bin/bash -G sudo alice\nSystem account: useradd -r -s /sbin/nologin serviceuser\nAdd to group: usermod -aG docker alice\nLock: usermod -L alice\nDelete: userdel -r alice (removes home dir)\nPassword aging: chage -M 90 alice (max 90 days)\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/009-lvm-workflow lpic-lfcs hard lpic, lfcs, storage, lvm What is the complete LVM workflow from physical volume to mounted filesystem? 1. pvcreate /dev/sdb (create PV)\n2. vgcreate datavg /dev/sdb (create VG)\n3. lvcreate -L 5G -n datalv datavg (create LV)\n4. mkfs.ext4 /dev/datavg/datalv (create filesystem)\n5. mount /dev/datavg/datalv /mnt/data\n6. Add to /etc/fstab with UUID\nExtend: lvextend -r -L +2G /dev/datavg/datalv (-r resizes filesystem too)\n\nRemember: LVM cmds: pv*(physical), vg*(group), lv*(logical). pvdisplay, vgextend, lvresize. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/010-fstab lpic-lfcs medium lpic, lfcs, storage, fstab What is the format of /etc/fstab and how do you use it safely? Format: device mountpoint fstype options dump pass\nExample: UUID=xxx /mnt/data ext4 defaults 0 2\nAlways use UUID (not /dev/sdX which can change).\nTest: sudo mount -a (verifies fstab without reboot).\nUse nofail for non-critical mounts to prevent boot failures.\nBad fstab entry = unbootable system!\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/011-iptables lpic-lfcs hard lpic, lfcs, networking, firewall How do you configure iptables rules for a basic server? Allow SSH: iptables -A INPUT -p tcp --dport 22 -j ACCEPT\nAllow HTTP: iptables -A INPUT -p tcp --dport 80 -j ACCEPT\nAllow established: iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT\nAllow loopback: iptables -A INPUT -i lo -j ACCEPT\nDefault deny: iptables -P INPUT DROP\nPersist (Debian): apt install iptables-persistent && netfilter-persistent save\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/012-ssh-hardening lpic-lfcs medium lpic, lfcs, ssh, security What are the essential SSH hardening settings? PermitRootLogin no\nPasswordAuthentication no\nPubkeyAuthentication yes\nConfig: /etc/ssh/sshd_config\nKey permissions: ~/.ssh/ (700), authorized_keys (600), private key (600)\nRestart: sudo systemctl restart sshd\nWrong permissions = SSH silently falls back to password auth.\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/013-lpic-vs-lfcs lpic-lfcs easy lpic, lfcs, exam What is the difference between LPIC-1 and LFCS certifications? LPIC-1: LPI, distro-neutral, multiple choice + fill-in, two exams (101+102), tests both Debian and RHEL knowledge.\nLFCS: Linux Foundation, hands-on performance-based, single exam, choose Ubuntu or CentOS environment. LFCS is closer to RHCSA in format.\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/014-grub-config lpic-lfcs medium lpic, lfcs, boot, grub How do you properly modify GRUB bootloader configuration? Edit /etc/default/grub (NOT /boot/grub/grub.cfg directly).\nRegenerate: sudo update-grub (Debian) or sudo grub2-mkconfig -o /boot/grub2/grub.cfg (RHEL).\nEditing grub.cfg directly = changes overwritten on next kernel update.\n\nRemember: Edit `/etc/default/grub` → `grub-mkconfig`. Never edit grub.cfg directly. training/library/topics/lpic-lfcs/footguns.md lpic-lfcs/015-tar-archives lpic-lfcs easy lpic, lfcs, archiving How do you create and extract tar archives with different compression? Create gzip: tar czf archive.tar.gz /path/\nCreate bzip2: tar cjf archive.tar.bz2 /path/\nExtract: tar xzf archive.tar.gz or tar xjf archive.tar.bz2\nExtract to dir: tar xzf archive.tar.gz -C /destination/\nList contents: tar tzf archive.tar.gz\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/016-process-signals lpic-lfcs medium lpic, lfcs, processes What are the key process signals and how do you send them? SIGTERM (15): graceful termination (default kill)\nSIGKILL (9): force kill (cannot be caught)\nSIGHUP (1): reload config (many daemons)\nSIGSTOP/SIGCONT: pause/resume\nSend: kill PID, kill -9 PID, kill -HUP PID\nBy name: killall nginx, pkill -f "pattern"\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/017-apache-debian lpic-lfcs medium lpic, lfcs, apache, debian How does Apache virtual host management work on Debian/Ubuntu? Config: /etc/apache2/sites-available/\nEnable: sudo a2ensite mysite.conf\nDisable: sudo a2dissite mysite.conf\nEnable module: sudo a2enmod rewrite ssl\nDisable module: sudo a2dismod php\nTest: sudo apache2ctl configtest\nReload: sudo systemctl reload apache2\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/street_ops.md lpic-lfcs/018-crontab-format lpic-lfcs easy lpic, lfcs, cron What is the crontab time format? Five fields: minute hour day-of-month month day-of-week\nExample: */5 * * * * command (every 5 minutes)\n0 2 * * 0 command (Sundays at 2am)\nEdit: crontab -e\nList: crontab -l\nOther user: sudo crontab -u alice -e\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/019-swap-management lpic-lfcs medium lpic, lfcs, storage, swap How do you create and manage swap space on Linux? Create swap partition: mkswap /dev/sdb2\nEnable: swapon /dev/sdb2\nDisable: swapoff /dev/sdb2\nCheck: free -h, cat /proc/swaps\nCreate swap file: dd if=/dev/zero of=/swapfile bs=1M count=1024 && mkswap /swapfile && swapon /swapfile\nPersist in /etc/fstab: /swapfile none swap sw 0 0\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md lpic-lfcs/020-kernel-modules lpic-lfcs medium lpic, lfcs, kernel How do you manage Linux kernel modules? List loaded: lsmod\nLoad: sudo modprobe module_name\nUnload: sudo modprobe -r module_name\nInfo: modinfo module_name\nAuto-load at boot: /etc/modules-load.d/\nBlacklist: echo "blacklist module_name" > /etc/modprobe.d/blacklist-mod.conf\n\nRemember: LPIC/LFCS exams are hands-on. Practice on real systems, not just theory.\n\nGotcha: Know default file paths and command flags for the exam. training/library/topics/lpic-lfcs/primer.md --- ## Wiki Navigation ### Related Content - [LPIC / LFCS Exam Preparation](../../../../library/topics/lpic-lfcs/index.md) (Topic Pack, L2) — LPIC / LFCS Exam