Basic Linux Commands & Help

List directory contents.

Change the current directory.

Print the current working directory.

Copy files or directories.

Move or rename a file or directory.

Remove files or directories.

Create a directory (with -p, create parents as needed).

Create an empty file, or update its modification time.

Search a directory tree for files matching criteria.

Create a hard or (with -s) symbolic link.

Show a directory's contents as a tree.

Change a file or directory's permissions.

Change a file or directory's owner and group.

Show or set the default permission mask for new files.

Change extended file attributes, e.g. making a file immutable.

Show running processes.

Live view of running processes and resource usage.

Interactive, colorized alternative to top (not installed by default).

Send a signal (default TERM) to a process.

Send a signal to all processes matching a name.

Run a command with an adjusted scheduling priority.

Run a command immune to hangups, so it keeps running after logout.

List background jobs in the current shell.

Resume a stopped job in the background or foreground.

Send ICMP echo requests to test reachability.

Transfer data to/from a URL — the go-to tool for testing HTTP.

Download a file from a URL.

Show socket statistics — the modern replacement for netstat.

Show network connections, routing tables, and interface stats (legacy).

Query DNS records for a domain.

Query DNS records (simpler, older alternative to dig).

Show the network path (hops) to a host.

Show/manipulate routing, network devices, and addresses.

Open a secure shell session on a remote host.

Copy files over SSH.

Efficiently sync files/directories, locally or over SSH.

Netcat — read/write raw TCP or UDP connections; handy for quick port tests.

Package manager for Debian/Ubuntu.

Package manager for RHEL/CentOS/Fedora.

Install/query low-level .deb packages directly.

Install/query low-level .rpm packages directly.

Install sandboxed snap packages.

Show disk space usage per filesystem.

Show disk usage of files/directories.

Mount a filesystem.

Unmount a filesystem.

List block devices (disks and partitions) as a tree.

Partition a disk, or list partitions with -l.

Low-level copy of raw data between devices/files — powerful and unforgiving.

Print the current effective username.

Show a user's UID, GID, and group memberships.

Create a new user account.

Modify an existing user account, e.g. adding a group.

Change a user's password.

Switch to another user's shell.

Run a command as another user (default root) per /etc/sudoers.

Show who is currently logged in.

Search text for lines matching a pattern.

Stream editor for filtering and transforming text.

Pattern-scanning and text-processing language.

Print a file's contents to stdout.

View a file one screen at a time, scrollable.

Show the start/end of a file; -f follows new lines as they're written.

Extract columns/fields from each line of a file.

Sort lines of text.

Filter out (or count) repeated adjacent lines — usually piped after sort.

Count lines, words, or bytes in a file.

Show differences between two files.

Build and run commands from piped input.

Archive files; -c create, -x extract, -z gzip, -f filename.

Print system/kernel information.

Show how long the system has been running plus load averages.

Show memory and swap usage.

Report virtual memory, CPU, and I/O statistics.

Report CPU and per-device I/O statistics (part of sysstat).

Collect and report historical system activity (part of sysstat).

Show kernel ring buffer messages — useful for hardware/driver issues.

Query and follow the systemd journal (logs).

Show this shell session's command history.

Show the current environment variables.

Show a service's current status.

Start or stop a systemd service.

Make a service start automatically on boot.

Reload unit files after editing one, before restarting the service.

Compress or decompress a single file.

Create or extract a .zip archive.