Day 2 — File Operations: touch, mkdir, rm, cp, mv#

Goal: Master the essential file management commands so you can create, copy, move, rename, and delete files and directories entirely from the terminal.

Creating Files — `touch`#

touch creates an empty file (or updates the timestamp of an existing file).

touch notes.txt                    # create one empty file
touch file1.txt file2.txt file3.txt  # create multiple files
touch ~/projects/README.md         # create in a specific location

If the file already exists, touch updates its “last modified” time without changing content.

ls -l notes.txt
# -rw-r--r-- 1 alice alice 0 Jan 15 10:00 notes.txt

touch notes.txt
ls -l notes.txt
# -rw-r--r-- 1 alice alice 0 Jan 15 10:05 notes.txt  ← timestamp updated

Creating Directories — `mkdir`#

mkdir mydir                             # create one directory
mkdir dir1 dir2 dir3                    # create multiple directories
mkdir -p parent/child/grandchild        # create nested path (-p = parents)
mkdir -p project/{src,tests,docs,data}  # brace expansion: create four dirs

The -p flag is critical:

Without -p: fails if parent directories don’t exist
With -p: creates all missing parents, no error if it already exists

# Without -p — fails:
mkdir a/b/c
# mkdir: cannot create directory 'a/b/c': No such file or directory

# With -p — works:
mkdir -p a/b/c     # creates a/, a/b/, and a/b/c/

Copying Files — `cp`#

# Copy a file
cp source.txt destination.txt

# Copy a file to a directory
cp report.pdf ~/backup/

# Copy with a new name into a directory
cp report.pdf ~/backup/report-v2.pdf

# Copy all .csv files to a folder
cp *.csv ~/data/

# Copy a DIRECTORY (must use -r)
cp -r myproject/ myproject-backup/

Important flags#

cp -r   # recursive — REQUIRED for directories
cp -i   # interactive — asks before overwriting
cp -v   # verbose — shows what's being copied
cp -p   # preserve — keeps original permissions and timestamps

Common mistake#

# This fails — cp requires -r for directories:
cp mydir/ backup/
# cp: -r not specified; omitting directory 'mydir/'

# Correct:
cp -r mydir/ backup/

Moving and Renaming — `mv`#

mv does two things: move files to a new location, and rename files.

# Rename a file (same directory, different name)
mv old-name.txt new-name.txt

# Move a file to another directory
mv report.txt ~/archive/

# Move AND rename
mv ~/Downloads/data.csv ~/projects/tds/raw-data.csv

# Move multiple files to a directory
mv *.log ~/logs/

# Rename a directory
mv old-project/ new-project/

Important flags#

mv -i   # interactive — asks before overwriting
mv -v   # verbose — shows what's being moved

Key difference: mv does NOT keep the original. It’s cut+paste, not copy+paste. If you want to keep the original, use cp.

🧠 Knowledge Check#

Q1: You want to rename a file named report_draft.txt to report_final.txt. Which command should you use?

A) cp report_draft.txt report_final.txt
B) rename report_draft.txt report_final.txt
C) mv report_draft.txt report_final.txt
D) touch report_final.txt

Answer

C — The mv (move) command is used for both moving files to new directories AND renaming files.

Deleting Files — `rm`#

⚠️ WARNING: rm is permanent. There is no Recycle Bin. Files are gone.

# Delete a file
rm file.txt

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

# Delete all .tmp files
rm *.tmp

# Delete a directory and everything inside it
rm -r mydir/

# Force delete (no prompts, no errors for missing files)
rm -rf mydir/

Important flags#

rm -r   # recursive — REQUIRED for directories
rm -f   # force — no confirmation prompts
rm -i   # interactive — asks before each deletion (safer)
rm -v   # verbose — shows what's being deleted

Safety tips#

# SAFE: use -i to confirm each deletion
rm -i *.csv
# rm: remove regular file 'data1.csv'? y
# rm: remove regular file 'data2.csv'? n   ← skipped!

# DANGEROUS — never run these:
rm -rf /           # deletes EVERYTHING on your system
rm -rf ~           # deletes your entire home directory
rm -rf .           # deletes everything in current directory

sudo apt install trash-cli -y
trash file.txt         # moves to trash instead of deleting
trash-list             # see what's in trash
trash-restore          # bring files back

🧠 Knowledge Check#

Q1: What is the safest way to delete multiple files using wildcards?

A) Use rm -rf *
B) Use rm -i so it prompts you for confirmation before each deletion
C) Use rm -f
D) You cannot delete multiple files with rm

Answer

B — The -i (interactive) flag is crucial for safety, especially when using wildcards, as it asks for confirmation before deleting each file.

Removing Empty Directories — `rmdir`#

rmdir emptydir/      # only works if the directory is empty
# rmdir: failed to remove 'emptydir/': Directory not empty

# If it has contents, use rm -r instead:
rm -r nonemptydir/

Wildcards (Glob Patterns)#

Wildcards let you match multiple files at once:

Pattern	Matches	Example
`*`	Zero or more characters	`*.py` → all Python files
`?`	Exactly one character	`file?.txt` → `file1.txt`, NOT `file10.txt`
`[abc]`	One character from the set	`file[123].txt` → `file1.txt`, `file2.txt`, `file3.txt`
`[a-z]`	One character in the range	`[A-Z]*.py` → Python files starting with uppercase

# Examples:
ls *.md                  # all Markdown files
rm temp_*.log            # all files matching temp_*.log
cp data_[0-9].csv backup/ # data_0.csv through data_9.csv
mv report?.pdf archive/  # report1.pdf, reportA.pdf (single char)

Quick Reference#

Command	Purpose	Key flag
`touch`	Create empty file / update timestamp	—
`mkdir`	Create directory	`-p` (create parents)
`cp`	Copy file or directory	`-r` (required for dirs)
`mv`	Move or rename	`-i` (ask before overwrite)
`rm`	Delete permanently	`-r` (dirs), `-i` (safe)
`rmdir`	Delete empty directory	—

Q&A#

Q: What is the difference between cp and mv?

cp = copy — the original file stays. You now have two copies.
mv = move — the original is gone. The file is now at the new location.

Think of it as copy+paste vs cut+paste.

Q: Why do I need -r for directories but not for files?

A: A directory can contain other directories, which contain other directories, etc. The -r (recursive) flag tells the command to go into every subdirectory. Without it, the command would only work on single files, which is a safety measure to prevent accidental bulk operations on directories.

Q: Is there a way to undo rm?

A: No. Once a file is deleted with rm, it is gone permanently. There is no trash or undo. Prevention strategies:

Use rm -i to get confirmation prompts
Install trash-cli for a trash-can workflow
Use version control (Git) — committed files can always be recovered

Q: What does touch do if the file already exists?

A: It updates the file’s “last modified” timestamp to the current time without changing the contents. This is sometimes useful for triggering build systems that watch file modification times.

Exercises#

Exercise 1: File operations practice

# Create a practice area:
mkdir -p /tmp/file-ops-practice
cd /tmp/file-ops-practice

# Create files:
touch apple.txt banana.txt cherry.txt grape.csv melon.csv

# List them:
ls -la

Now perform these tasks:

Copy apple.txt to apple-backup.txt
Rename banana.txt to yellow-fruit.txt
Create a directory called fruits/
Move all .txt files into fruits/
Delete melon.csv

Solution

# 1. Copy
cp apple.txt apple-backup.txt

# 2. Rename
mv banana.txt yellow-fruit.txt

# 3. Create directory
mkdir fruits

# 4. Move all .txt files
mv *.txt fruits/

# 5. Delete
rm melon.csv

# Verify:
ls                    # grape.csv  fruits/
ls fruits/            # apple-backup.txt  apple.txt  cherry.txt  yellow-fruit.txt

Exercise 2: Directory operations

# Create this structure in one command:
mkdir -p /tmp/project/{src,tests,docs,data/{raw,processed}}

# Verify:
tree /tmp/project/

Expected tree output

/tmp/project/
├── data
│   ├── processed
│   └── raw
├── docs
├── src
└── tests

Now copy the entire project:

cp -r /tmp/project/ /tmp/project-backup/
tree /tmp/project-backup/

What should you see?

The exact same structure under /tmp/project-backup/. The -r flag copied everything recursively.

Exercise 3: Wildcard practice

cd /tmp
touch report1.txt report2.txt report10.txt summary.txt data.csv

# Which command lists only report1.txt and report2.txt (not report10.txt)?

Answer

ls report?.txt
# report1.txt  report2.txt

The ? matches exactly one character, so report?.txt matches report1.txt and report2.txt but NOT report10.txt (which has two characters after “report”).

To match all report files including report10.txt:

ls report*.txt
# report1.txt  report10.txt  report2.txt

Exercise 4: MCQ

Q1: Which command copies a directory src/ to src-backup/?

A) cp src/ src-backup/
B) cp -r src/ src-backup/
C) mv src/ src-backup/
D) mkdir src-backup/ && cp src/ src-backup/

Answer

B — cp -r (recursive) is required for copying directories. Option A fails without -r. Option C moves (doesn’t keep the original).

Q2: What happens when you run rm -rf /tmp/test/ if /tmp/test/ doesn’t exist?

A) Error message displayed
B) Nothing happens (silent success)
C) Creates the directory
D) Deletes /tmp/ instead

Answer

B — The -f flag suppresses errors for non-existent files. Without -f, you’d get rm: cannot remove '/tmp/test/': No such file or directory.

Q3: You have files a.csv, b.csv, c.csv, notes.txt. Which command deletes only the CSV files?

A) rm *
B) rm *.csv
C) rm ?.csv
D) rm csv

Answer

B — *.csv matches all files ending in .csv. Option A deletes everything. Option C matches only single-character names before .csv.

Clean up all exercise files:

rm -rf /tmp/file-ops-practice /tmp/project /tmp/project-backup
rm /tmp/report1.txt /tmp/report2.txt /tmp/report10.txt /tmp/summary.txt /tmp/data.csv

Day 2 — File Operations: touch, mkdir, rm, cp, mv#

Creating Files — touch#

Creating Directories — mkdir#

Copying Files — cp#

Important flags#

Common mistake#

Moving and Renaming — mv#

Important flags#

🧠 Knowledge Check#

Deleting Files — rm#

Important flags#

Safety tips#

🧠 Knowledge Check#

Removing Empty Directories — rmdir#

Wildcards (Glob Patterns)#

Quick Reference#

Q&A#

Exercises#

Creating Files — `touch`#

Creating Directories — `mkdir`#

Copying Files — `cp`#

Moving and Renaming — `mv`#

Deleting Files — `rm`#

Removing Empty Directories — `rmdir`#