Linux and DevOps Cheat Sheets

podman runs OCI containers and pods without a central daemon. On RHEL, Rocky Linux, AlmaLinux, and Fedora it is the default container CLI — pull images, run rootless workloads, manage volumes and networks, and integrate …

sysctl reads and writes kernel tunables exposed under /proc/sys. Use it to inspect dotted parameter names, set runtime values with -w, filter keys with -a -r, and load drop-in files with -p or --system.

Scan-first Terraform cheat sheet for CLI commands, configuration files, HCL syntax, variables, expressions, count and for_each, state and import, modules, workspaces, and debugging — with links to full tutorials.

RHCSA cheat sheet for RHEL 10 EX200 revision—compact command patterns, verification commands, and lesson links by objective area. Not a general Linux command index.

journalctl reads logs collected by systemd-journald — kernel messages, service output, boot sessions, and syslog traffic in one queryable journal. Filter by unit, time, priority, boot, and process fields without hunting …

Scan-first CKAD command reference for kubectl dry-run YAML generation, apply and patch, JSONPath, rollouts, Helm, Kustomize, probes, and troubleshooting with links to course lessons.

kubectl applies declarative YAML, generates manifests with dry-run, patches live objects, and filters output with JSONPath and custom columns on any Kubernetes cluster.

tmux is a terminal multiplexer that keeps shell sessions running in the background, splits one screen into panes and windows, and reconnects after SSH drops. Default prefix is Ctrl+b.

virt-install provisions KVM guests through libvirt from ISO, install trees, PXE, or existing disk images. Use it to set CPU, memory, disks, networks, and graphics before the guest boots.

Use dsconf to manage a running 389 Directory Server: backends, indexes, replication, plug-ins, logs, security, schema, monitoring, and online backups.

pidstat from the sysstat package reports per-process and per-thread CPU, memory, disk I/O, and context-switch statistics on Linux. Use it to find which PID is driving load during an incident.

mpstat from the sysstat package reports per-processor CPU utilization, NUMA node stats, and interrupt rates on Linux. Use it to find hot CPUs, IRQ load, and uneven scheduling across cores.

ldapadd creates LDAP entries from LDIF input. Use a StartTLS-protected simple bind for directory data or SASL EXTERNAL over LDAPI for local cn=config schema work.

ldapdelete removes LDAP entries by distinguished name. It supports one or more DNs on the command line, a DN file, and recursive subtree deletion when a non-leaf entry must be removed.

ldapmodify applies LDIF changes to LDAP entries. It adds, replaces, or deletes attributes using a StartTLS simple bind, and can modify local cn=config through LDAPI SASL EXTERNAL.

ldapsearch queries LDAP directory entries from the command line. It can search anonymously, use a simple bind protected by StartTLS, or authenticate locally over LDAPI with SASL EXTERNAL.

ldapwhoami performs the LDAP Who Am I extended operation after a bind. It is a compact way to verify the authorization identity seen by an OpenLDAP server.

slappasswd generates RFC 2307 password values for OpenLDAP userPassword attributes and the cn=config olcRootPW setting on RHEL-family LDAP servers.

dsidm manages directory data in a 389 Directory Server instance — organizational units, POSIX users and groups, groupOfNames, service accounts, roles, and client configuration snippets. Server tuning stays in dsconf; …

dsctl manages local 389 Directory Server instances on the host — start and stop ns-slapd, list instances, run offline backups and LDIF exports, inspect TLS certificates, and remove instances. It does not change online …

slapadd imports LDIF directly into an offline OpenLDAP backend for controlled restores and initial loads on RHEL-family servers with openldap-servers.

slapcat exports an OpenLDAP server database to LDIF for offline backup, migration, and inspection on RHEL-family systems using openldap-servers.

slaptest parses and checks OpenLDAP slapd configuration before service startup or a configuration change on RHEL-family servers using openldap-servers.

The Linux audit framework logs security-relevant events through auditd. Use auditctl to define rules, ausearch to query the audit log, and aureport for summaries — with augenrules to load persistent policy on RHEL-family …

nft is the userspace CLI for the Linux nftables firewall framework. Define tables, chains, and rules in the netfilter stack — list the live ruleset, load rule files, and debug filtering alongside firewalld on RHEL-family …

cryptsetup manages LUKS disk encryption through the kernel dm-crypt device mapper. Use it to format partitions, open and close mapper devices, rotate passphrases, back up headers, and inspect LUKS2 metadata on Ubuntu and …

nmcli is the command-line client for NetworkManager. It lists devices and connections, sets IPv4/IPv6 addresses, DNS, routes, hostname, and applies profile changes without editing ifcfg files by hand.

A complete Linux commands cheat sheet with 100+ essential commands and practical examples. Learn file management, system monitoring, networking, permissions, and DevOps-related Linux commands used by administrators, …

keytool is the Java CLI for keystores and truststores: generate key pairs, build CSRs, import CA-signed certificates and PKCS12 bundles, list aliases, export PEM certs, and manage passwords. This cheat sheet covers …

OpenSSL is the standard CLI for TLS keys, X.509 certificates, CSRs, chain verification, PKCS#12 bundles, file encryption, and live HTTPS inspection. This cheat sheet covers everyday subcommands with copy-paste tables and …