Files, Directories & Paths

Quick check: What does cd .. do? If you know, skip to File Operations.

Practice these topics: File Navigation · File Operations · Wildcards

After this lesson, you will be able to:

• Create directories with mkdir and mkdir -p
• Navigate with cd using .., ~, and -
• Copy, move, rename, and delete files and directories
• Use wildcards (*, ?, [...]) to match multiple files
• View file contents with cat, head, tail

Building Your Workspace

In CSCD 210, VS Code managed your files. Now you build the structure yourself.

cd ~                          # go home
mkdir cscd240                 # create course directory
mkdir -p cscd240/lab1/src     # create nested dirs in one step

mkdir -p creates all intermediate directories. Without -p, the command fails if a parent does not exist.

Navigation: cd

cd cscd240          # move into cscd240
cd lab1/src         # relative path (from where you are)
cd /home/student    # absolute path (from root)
cd ..               # up one level
cd ../..            # up two levels
cd ~                # home directory
cd -                # toggle to previous directory

Key Insight: cd - toggles between your last two directories. This is the single most useful navigation shortcut when you are working in two places.

Creating Files

touch hello.c Makefile    # creates empty files (or updates timestamps)

You will fill these files with code starting in Week 4.

Viewing Files

cat notes.txt       # print entire file
head -5 notes.txt   # first 5 lines
tail -3 notes.txt   # last 3 lines
wc -l notes.txt     # count lines

cat is fine for short files. For long files, use less (scroll with arrows, quit with q).

Copying, Moving, and Deleting

cp hello.c backup.c         # copy file
cp -r lab1 lab1-backup      # copy directory (requires -r)
mv backup.c old_hello.c     # rename
mv old_hello.c ../          # move to parent directory
rm old_hello.c              # delete file (PERMANENT)
rm -r lab1-backup           # delete directory and contents

Common Pitfall: rm is permanent. There is no trash can, no undo. Always ls before you rm. Use rm -i for interactive confirmation until you trust your typing.

Wildcards

The shell expands wildcards before the command runs:

ls *.c              # list all C source files
rm *.o              # remove all object files

What Comes Next

You can create, navigate, copy, move, and delete. Next week starts with man pages and getting help when you are stuck.