Essential Linux Commands: ls, cd, mkdir, rm, cp (Tested on Rocky Linux 9)

When you take over a Linux machine, the daily operations come down to the same handful: list directories, change directories, create directories, delete things, copy things. This post pairs each of these five most basic commands with a real output example — all captured from actual runs in a Rocky Linux 9 container. Usage is exactly the same on CentOS 7.

ls: List Directory Contents

ls displays the files and subdirectories inside a directory. Common options:

Option	Effect
-l	Show detailed information in list format
-a	Show all files, including hidden ones
-h	When used with -l, converts byte counts into readable units like K and M

A detailed listing of all files in the current directory (including hidden ones):

ls -la

Tested output (root’s home directory, excerpted):

ls test

The first character at the start of each line indicates the entry type: d means a directory, - means a regular file; . and .. stand for the current directory and the parent directory, respectively.

cd: Change the Working Directory

cd changes your current working directory. It produces no output itself, so confirm with pwd afterwards:

1	cd /var/log && pwd

Tested output: /var/log (shown in the same screenshot as the mkdir test below). The current directory name in your prompt also changes along with it — a quick confirmation when you don’t feel like typing pwd.

mkdir: Create New Directories

mkdir creates new directories; the -p option also creates missing parent directories along the way:

1	mkdir -p /root/a/b/c

Check the result recursively with ls -R. Tested: the entire path was created in one shot:

cd and mkdir test

Without -p, running mkdir /root/a/b/c directly errors out because /root/a and /root/a/b don’t exist — -p fills in the whole path.

rm: Delete Files and Directories

rm deletes files or directories. Two options to memorize:

Option	Effect
-r	Delete directories recursively, along with their contents
-f	Force deletion; ignore nonexistent files, no prompts along the way

Recursive deletion with verification. Tested: getting No such file or directory is precisely the proof that everything was deleted:

rm test

cp: Copy Files or Directories

cp copies files or directories. Common options:

Option	Effect
-r	Copy directories and their contents
-i	Prompt before overwriting files
-u	Copy only when the source is newer than the destination, or when the destination doesn’t exist

Build a directory with a file in it, then copy it, and inspect both sides. Tested: the copy succeeded and the original directory remained:

cp test

Copying a directory requires -r: without it, GNU cp reports cp: -r not specified; omitting directory and skips the directory entirely. To verify the contents match, run diff -r a d — no output means both sides are identical.

Notes and Cautions

rm -rf has no recycle bin — once deleted, it’s gone. Read the path twice before executing, especially with wildcards involved.
For large file listings, use ls -lh; -h converts byte counts into readable units like K and M.
mkdir -p creates the entire path in one shot; always include it in scripts to save yourself a pile of existence checks.
Remember -r when copying directories (tested: without -r, GNU cp reports -r not specified; omitting directory); add -i if you don’t want destination files silently overwritten.