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Linux — File Management

Short & clear revision notes · 8 topics

01 · What is File Management?

In Linux, everything is a file — documents, programs, and even hardware devices. File management means creating, viewing, editing, copying, moving, and deleting these files.

All files live inside directories arranged in a tree structure starting from / (the root). This entire structure is called the filesystem.

📚 Think of it like a library — the building is the filesystem, shelves are directories, and books are files. Every file has a fixed location you can navigate to.

02 · Types of Files

Linux has three basic types: ordinary files (text, images, scripts), directories (folders), and special files (hardware/communication). When you run ls -l, the first character shows the file type:

Symbol File Type Example
- Regular file text, scripts, images, binaries
d Directory a folder containing other files
l Symbolic link a shortcut pointing to another file
b Block device hard drive, USB drive
c Character device keyboard, modem
p Named pipe lets two programs share data
s Socket used for network/app communication

03 · Listing Files — ls

Command What it does
ls List all files in the current directory
ls -l Detailed view: type, permissions, owner, size, date
ls -a Show hidden files too (files starting with a dot)
ls *.doc Only .doc files — * matches any characters
ls ch?.doc Match ch1.doc, chA.doc — ? matches exactly one character

The 7 columns in ls -l

1            2       3      4      5     6              7
type+perms   links   owner  group  size  last-modified  filename
-rw-r--r--   1       rauneet users  116   Apr 06 10:00   notes.txt
# Column Meaning
1 type + permissions file type + who can read/write/execute
2 link count number of hard links to this file
3 owner user who owns the file
4 group group the file belongs to
5 size file size in bytes
6 last modified date and time of last change
7 file name name of the file

04 · Hidden Files

Any file whose name starts with a . (dot) is hidden — it won't appear in a normal ls. These are usually system configuration files. Use ls -a to reveal them.

File Purpose
.profile Runs on login — Bourne shell startup config
.kshrc Korn shell startup config
.cshrc C shell startup config
.rhosts Remote shell access config

💡 In every directory: . means the current directory and .. means the parent directory (one level up).

05 · Creating & Editing Files — vi

vi (or vim) is a text editor built into every Linux system. It has two modes — you must switch between them to type or navigate. It always opens in normal mode, so press i before you start typing.

Key / Command What happens
vi filename Open file (creates it if it doesn't exist)
i Switch to insert mode — now you can type
Esc Go back to normal mode (for navigation)
Shift + ZZ Save the file and exit vi
h / l Move cursor left / right
k / j Move cursor up / down

Quick workflow

vi notes.txt  →  press i  →  type content  →  press Esc  →  press Shift+ZZ
  (open)         (insert)     (write)          (normal)       (save & quit)

06 · Viewing File Content — cat & wc

Use cat to read a file and wc to count its lines, words, and bytes.

Command What it does
cat filename Print the entire file contents on screen
cat -b filename Same, but with line numbers shown
wc filename Shows: lines · words · bytes · filename
wc f1 f2 f3 Count stats for multiple files at once

Example output: 2 22 116 notes.txt → 2 lines, 22 words, 116 bytes

07 · Copy, Rename & Delete Files

Command What it does
cp src dest Copy a file — the original stays untouched
mv old new Rename a file — old name no longer exists
mv file /path/ Move a file to a different directory
rm filename Permanently delete a file
rm f1 f2 f3 Delete multiple files at once
rm -i filename Ask for confirmation before deleting (safer)

⚠️ There is NO Recycle Bin in Linux. Once deleted with rm, a file is gone forever. Always prefer rm -i until you are confident.

08 · Links — Hard Link vs Symbolic Link

A link is an alternate name or path to access the same file. Linux supports two types:

Hard Link Symbolic Link (Soft Link)
What it is Another name for the exact same file data A shortcut pointing to the original by path
If original deleted File still exists (data stays) Symlink breaks (points to nothing)
Analogy Two equal front doors to the same room A signpost pointing to the room
Command ln file hardlink ln -s file symlink

💡 Deleting a link (either type) never deletes the original file. You can edit a file through its link just like through its real name.

Linux File Management Notes — for revision use