Zsh Lesson 3: File Operations — touch, mkdir, cp, mv, rm, Wildcards

touch file creates empty (or updates mtime). mkdir -p path creates nested dirs. cp src dst, mv src dst. rm deletes — no Trash, no undo. Wildcards: * any chars, ? one char, [abc] set.

The five commands you'll use to create, copy, rename, and delete files. Sandbox first:

mkdir -p ~/zshshell-practice && cd ~/zshshell-practice

So nothing important gets touched.

touch: create or update

touch myfile.txt
ls -la myfile.txt
# -rw-r--r--  1 alice  staff  0 May  8 10:00 myfile.txt

touch path creates an empty file at path if it doesn't exist. If it does exist, it updates the modification time.

Multiple files at once:

touch file1.txt file2.txt file3.txt
ls -la *.txt

mkdir: create directories

mkdir myproject
ls -la

Creates a single directory.

For nested paths, -p creates parents as needed:

mkdir -p projects/webapp/src/components

Without -p, that errors if projects/ doesn't exist. With -p, also no error if the directory already exists. Always use -p — it's idempotent.

cp: copy

# Copy file to a new name
cp myfile.txt backup.txt

# Copy file INTO a directory (trailing slash makes it explicit)
cp myfile.txt myproject/

# Copy a directory recursively
cp -r myproject myproject_backup

-r (or -R) recursively copies a directory and all its contents. Without -r, copying a directory errors.

For preserving permissions, timestamps, and links:

cp -a src dst    # archive mode — like -r but preserves more metadata

mv: move and rename

# Rename
mv backup.txt renamed.txt

# Move file into a directory
mv renamed.txt myproject/

# Move and rename simultaneously
mv old.txt myproject/new.txt

mv doesn't have a separate "rename" command — moving to the same directory with a different name is renaming.

Same syntax for directories — no -r needed for mv:

mv old_dir new_dir

rm: delete (DESTRUCTIVE)

rm file1.txt
rm file2.txt file3.txt    # multiple files

There is no Trash. Files deleted via rm are gone.

For directories:

rm -r myproject_backup      # recursive
rm -rf myproject_backup     # recursive + force (no prompts, no errors on missing)

rm -rf is the most dangerous command in shell. Aimed at the wrong directory — say with a typo, or with $VAR that's accidentally empty making rm -rf $VAR/* become rm -rf /* — it can wipe your system.

Safer habits:

# 1. Always preview with ls first
ls files_to_delete*

# 2. Use -i for confirmation
rm -i file.txt
rm -ri directory/

# 3. Quote variables
rm -rf "$DIR/sub"

For irreplaceable files: don't use rm. Use Finder's "Move to Trash" via mv file ~/.Trash/ — gives you a chance to undo.

Wildcards (globbing)

Wildcards expand to matching filenames before the command runs.

# Setup
mkdir -p demo && cd demo
touch a.txt b.txt log1.txt log2.txt log3.txt

* — any number of characters

ls *.txt
# a.txt b.txt log1.txt log2.txt log3.txt

ls log*
# log1.txt log2.txt log3.txt

? — exactly one character

ls log?.txt
# log1.txt log2.txt log3.txt

ls log??.txt
# (nothing — needs exactly two chars after "log")

[abc] — one character from a set

ls log[12].txt
# log1.txt log2.txt

ls log[1-3].txt
# log1.txt log2.txt log3.txt

ls log[!2].txt   # negation in zsh — NOT 2
# log1.txt log3.txt

** — recursive (Zsh)

ls **/*.txt    # all .txt files in current dir AND subdirs

This is a Zsh-specific extension. In Bash, you'd need find.

Combining wildcards with commands

# Copy all .txt files into a backup dir
mkdir -p ../backup_txt
cp *.txt ../backup_txt/

# Move all log files into a logs dir
mkdir -p logs
mv log*.txt logs/

# Delete all temp files
rm temp*.tmp

Wildcards work with cp, mv, rm, ls, cat, anything that takes filenames.

Brace expansion: not a wildcard, but related

mkdir -p project/{src,test,docs}
# Creates project/src, project/test, project/docs

touch report_{2024,2025,2026}.txt
# Creates three files

Braces expand BEFORE the command runs — but they don't match existing files like wildcards do. They generate strings.

Globs that match nothing

ls *.foo
# zsh: no matches found: *.foo

By default, Zsh errors if a glob matches nothing. Bash silently passes the literal *.foo to the command. To get Bash-like behavior:

setopt nullglob   # match-nothing → empty list
# or
setopt nomatch    # the default — error

Most users set nullglob once in .zshrc.

Hidden files and globs

ls *           # NOT including .dotfiles
ls .*          # only dotfiles (and . and ..)
ls .?*         # dotfiles, excluding . and ..

By default, * doesn't match leading .. To include them:

setopt globdots

Permissions: chmod

A quick aside — created files default to rw-r--r-- (644). To make a script executable:

chmod +x script.sh

Lesson 6 covers this in detail.

A complete workflow

# Set up a project skeleton
mkdir -p myproject/{src,tests,docs}
cd myproject

# Create starter files
touch src/main.py src/utils.py
touch tests/test_main.py
touch docs/README.md

# Verify
ls -laR

# Quick edit (any editor works)
nano src/main.py

# Backup before risky edit
cp -a src src_backup

# After confirming the new src works, remove backup
rm -r src_backup

# Or move it somewhere
mv src_backup ../archive/

Standard create-edit-backup-delete cycle. Use it constantly.

Common stumbles

rm with no recovery. Triple-check before. There's no Trash — rm releases the disk blocks immediately.

Wildcard expanded to too much. rm *.txt in /etc/? You'd be sad. Always ls first to see what'll match.

Forgot -r on cp. cp src_dir dest_dir errors. Add -r.

Trailing slash matters for cp/mv. cp file.txt mydir — if mydir exists, copies into it; if not, creates a copy named mydir. cp file.txt mydir/ always treats mydir as a directory (and errors if it doesn't exist).

Spaces in filenames. mv old name new name fails. Quote: mv "old name" "new name". Better: avoid spaces.

mkdir without -p. mkdir a/b/c errors if a/ doesn't exist. Always mkdir -p.

rm -rf $VAR/* with empty $VAR. Becomes rm -rf /*. Always quote and validate variables before destructive operations:

[[ -n "$DIR" ]] || exit 1
rm -rf "$DIR"/*

What's next

Lesson 4: viewing files. cat, less, head, tail, nano.

Recap

touch file creates or updates timestamp. mkdir -p path creates nested dirs (idempotent). cp src dst copies (-r for directories). mv src dst moves and renames. rm deletes — no Trash, no undo; use -i for confirmation. Wildcards: * any, ? one, [abc] set, **/ recursive (Zsh). Brace expansion {a,b,c} generates strings. Quote paths with spaces; never rm -rf unquoted variables.

Next lesson: viewing and editing files.