LINUX · COMMAND LINE

How to list files in a directory

20 October 2026 · 5 minute read

The first command anyone learns is the one most people never learn properly. You type ls, you see names, you move on. Then one day a disk fills up and you need to know which file is eating it, or a deploy fails and you need to know who owns a config, and the plain ls you've been typing for years can't answer it. The good news is the answer was there the whole time. ls is not one command. It's a dozen, and the flags that turn it into a real tool are easy once you know they exist.

The short answer. To list files in a directory on Linux, run ls. Add -l for the long format with permissions, owner, size, and time. Add -a to see hidden files. Add -S to sort by size and -t by time. That covers most of what you'll ever need.

What ls actually does

ls is a command that lists the files and directories in a directory. Under the hood it reads the directory and prints what it finds. A directory on Linux is just a list of names and inode numbers, and ls walks that list. The plain form prints the names, sorted alphabetically, in columns that fit your terminal.

$ ls
Documents  Downloads  notes.txt  projects  scripts

That's the whole thing in its simplest form. Names, sorted, in columns. It's fast, it's fine, and it's the version everyone learns. The problem is it tells you nothing about the files. Which one is a directory? Which one is huge? Which one did I touch last? Plain ls can't say.

The long format is where the information lives

Add -l and each entry becomes a full line. This is the format you'll actually use once you know it exists.

$ ls -l
total 24
drwxr-xr-x 2 kc kc 4096 Oct 24 09:12 Documents
-rw-r--r-- 1 kc kc  512 Oct 23 16:40 notes.txt
-rw-r--r-- 1 kc kc 2048 Oct 24 08:01 deploy.sh

Read it left to right and each field is one fact.

• The first character is the type. d means directory, - means a regular file, l means a symlink.
• The next nine characters are the permissions, three groups of three. Read, write, execute for the owner, then the group, then everyone else.
• The number after that is the link count, then the owner, then the group.
• The number is the size in bytes. 4096 on a directory is normal, it's the size of the directory entry itself, not its contents.
• The date is the last modification time, then the name.

That one line answers most of the questions you'll ever ask a filesystem. Who owns this? What are the permissions? How big is it? When was it changed? All of it, in one command.

Hidden files are not secret, they're just hidden

Anything whose name starts with a dot is hidden from a plain ls. That's the whole mechanism. No security, no encryption, just a convention that dot files don't show up by default. Config files live in your home directory as dot files, so .bashrc, .ssh, and .git all stay out of the way until you ask for them.

$ ls -a
.  ..  .bashrc  .ssh  Documents  notes.txt

Two entries show up that you didn't expect. . is the current directory and .. is its parent. They're real entries in every directory, and -a shows them. If you don't want them cluttering the output, use -A instead, which shows hidden files but skips the dot and dot dot.

$ ls -A
.bashrc  .ssh  Documents  notes.txt

That's usually the one you want. Hidden files, no noise.

Sort by size and time when it matters

Two sorts come up constantly. Finding the file eating your disk, and finding what changed most recently.

$ ls -lS
total 24
-rw-r--r-- 1 kc kc 2048 Oct 24 08:01 deploy.sh
-rw-r--r-- 1 kc kc  512 Oct 23 16:40 notes.txt
drwxr-xr-x 2 kc kc 4096 Oct 24 09:12 Documents

-S sorts by size, largest first. When a disk fills up, this is the command that points you at the culprit. On the Kubernetes nodes I run, a filling disk is almost never the pods, it's a log file or an old image tarball, and ls -lhS names it in one line. Add -h to print sizes in human readable form, 2.0K instead of 2048, which makes the output far easier to scan.

$ ls -lhS
total 24K
-rw-r--r-- 1 kc kc 2.0K Oct 24 08:01 deploy.sh
-rw-r--r-- 1 kc kc  512 Oct 23 16:40 notes.txt
drwxr-xr-x 2 kc kc 4.0K Oct 24 09:12 Documents

For time, -t sorts by modification time, newest first. This is the one you reach for when you're trying to figure out what changed right before something broke.

$ ls -lt
total 24
drwxr-xr-x 2 kc kc 4096 Oct 24 09:12 Documents
-rw-r--r-- 1 kc kc 2048 Oct 24 08:01 deploy.sh
-rw-r--r-- 1 kc kc  512 Oct 23 16:40 notes.txt

Add -r to reverse either sort. ls -lSr is smallest first, ls -ltr is oldest first. The reverse time sort is a classic, it shows you the files nobody has touched in a while, which is often exactly the set you're looking for.

The ls flags at a glance

Here is every flag from this article in one table, what it does, and when to reach for it.

List one directory without leaving where you are

You don't have to cd into a directory to see what's in it. Pass the path to ls directly.

$ ls -l /var/log
total 128
-rw-r--r-- 1 root root 40960 Oct 24 09:00 syslog
-rw-r--r-- 1 root root  2048 Oct 24 08:00 auth.log

This is the version that shows up in real work constantly. You're somewhere else, you need to see what's in a directory, and you don't want to change where you are to do it. ls -l /path answers it in place.

Verify it works

Run these and check the output against what you expect.

$ ls
$ ls -l
$ ls -la
$ ls -lhS

Plain ls shows names. -l shows the long format. -la shows everything including hidden files. -lhS shows human readable sizes sorted largest first. If each one prints more detail than the last, you've got it.

The honest caveat

There are more flags. ls -R recurses into subdirectories, ls -d */ lists only directories, and the color output from ls --color is on by default in most distros. You don't need any of them to be productive. The four flags here, -l, -a, -S, and -t, cover the real work. Everything else is a refinement you'll pick up when a specific problem asks for it.

One thing worth knowing. ls is not a shell builtin, it's a real program, and it's part of GNU coreutils. That means it behaves the same on every Linux box you'll ever touch. Learn it once and it follows you.

The boring conclusion

ls is the first command you learn and the last one you master, because the plain version is enough until it isn't. The long format turns a list of names into a list of facts, and the sort flags point you at the file that matters. None of it is hard. It's just that nobody shows you the flags until you need them.

What's the ls flag you reach for that most people don't know?

Frequently asked questions

How do I list files in a directory in Linux?

Run ls to list the names of files and directories in the current directory. Add -l for the long format with permissions, owner, size, and time. Add -a to include hidden files. Add -S to sort by size and -t by time.

What is the difference between ls and ls -l?

ls prints just the names. ls -l prints the long format, one line per entry, with permissions, owner, group, size, and modification time. The long format is what you want when you need to know anything about the files, not just that they exist.

Why does ls not show hidden files?

Files and directories whose name starts with a dot are hidden by default. ls -a shows them, including the . and .. entries. ls -A shows them without those two, which is usually what you actually want.

How do I list files by size or time?

ls -lS sorts by size, largest first. ls -lt sorts by modification time, newest first. Add -r to reverse either one. Add -h to print sizes in human readable form.

How do I list only directories with ls?

Run ls -d */ to list only the directories in the current directory. The -d flag lists the directory entries themselves rather than their contents, and the */ glob matches only directories.

What does ls -la mean?

ls -la combines -l (long format) and -a (all files including hidden ones). It shows every file and directory, including dot files, with permissions, owner, size, and modification time.

Resources

Two references cover everything in this article and the flags I left out. Both are the primary sources, so what you read here matches what the tool actually does.

• GNU coreutils manual, ls invocation. The authoritative reference for every ls flag, straight from the project that ships it.
• ls(1) man page. The full flag list and exit status, the same text you get from man ls.

Next in the series. How to read a file with cat, less, tail, and head is the next rung in the ladder.