terminal 102: files without fear terminal 102: จัดการไฟล์โดยไม่ต้องกลัว

in terminal 101 you learned to look around — pwd, ls, cd. that was the safe part.

now you’re going to change things: create files, copy them, rename them, delete them. the commands are short and straightforward. one of them (rm) skips the Trash entirely, so this post is really about learning the commands and building one good habit around them.

learn five core commands, one important variation, and one safety habit. after that, files stop feeling mysterious.

what you’ll know by the end

• how to create an empty file (touch) and read a text file (cat / type)
• how to copy (cp), move (mv), and rename files — rename is just move-in-place
• how to delete files safely (rm) and delete a whole folder (rm -r)
• how to see hidden files (ls -a) and handle file names with spaces ("quotes")
• how to act on many files at once with * (a wildcard pattern)
• the one rule that prevents most mistakes: pause before rm

what this assumes

just terminal 101. if pwd, ls, and cd feel natural, you’re ready.

5 core commands + 1 important variation

the simulator below keeps most file-management commands the same on Mac and Windows so you can focus on the concepts first. on a real Windows machine, you may also run into other command names depending on the shell you’re using.

rename is just move. mv old.txt new.txt renames. mv notes.txt ~/Desktop/ moves. same command, different destination.

real Windows note: the simulator accepts touch, cp, mv, rm so you can focus on the concepts. on real PowerShell, touch is not built in — use New-Item notes.md instead. cp, mv, and rm exist on PowerShell as aliases for the real cmdlets, so they work as shown.

try it yourself

here’s a terminal you can practice in. it’s fake, so nothing can hurt your real computer, and it’s close enough to a real shell to practice the basics safely.

walk through this sequence:

1. pwd — confirm where you are
2. ls (Mac) or dir (Windows) — see what’s here
3. cd Desktop — step into Desktop
4. touch todo.md — create an empty file
5. ls (Mac) or dir (Windows) — your new file is there
6. cat notes.txt (Mac) or type notes.txt (Windows) — read an existing file
7. cp notes.txt notes.bak — copy it
8. mv notes.bak old-notes.txt — rename the copy
9. rm old-notes.txt — delete the copy
10. ls (Mac) or dir (Windows) — confirm it’s gone

no dialog. no Trash. if you delete it, it’s gone. that’s why rm deserves extra care.

the real-world task

this one’s small, but it’s a workflow you’ll use constantly. do it in the terminal above:

1. cd ~ — head home
2. touch README.md — create it
3. cp README.md README.bak — make a backup
4. mv README.bak README.old — rename the backup
5. ls (Mac) or dir (Windows) — both files are there
6. rm README.old — delete the backup
7. ls (Mac) or dir (Windows) — only README.md remains

create → copy → rename → delete. almost every project includes some version of this.

hidden files and the . prefix

files and folders starting with a dot (.gitignore, .env, .zshrc) are hidden by default. ls won’t show them. you’ll meet plenty of them soon — every project has a .gitignore, every shell config is a dotfile.

see them all with -a:

ls -a          # Mac and Windows (both supported here)

try cd ~ then ls -a in the simulator. the .zshrc file appears only when you ask to show hidden files.

they’re not secret. the dot is just a convention that says “config file — don’t clutter the normal listing.”

names with spaces

if a file or folder has a space in its name, the terminal treats each word as a separate piece of the command. solution: wrap it in quotes.

cd "My Documents"
cat "weekly notes.md"

easier option: avoid spaces in names you create yourself. use - or _ instead. weekly-notes.md will save you trouble for the next decade.

acting on many files with *

* means “anything.” this kind of pattern is often called a glob.

ls *.pdf          # list every PDF
ls *.txt *.jpg    # list every txt and every jpg
rm *.bak          # delete every backup file (careful!)

try cd Desktop then ls *.pdf (Mac) or dir *.pdf (Windows) in the terminal above. the shell expands *.pdf into every matching file before running the command.

tip: before running rm *.something, swap the rm for ls first. if ls shows the right list, then run rm. this is a simple habit that prevents a lot of avoidable mistakes.

why rm matters more than the others

rm does not use the Trash. there is no confirmation dialog. if you delete the wrong file, your only easy way back is a backup or cloud sync that was already set up beforehand.

there are only two rules you need:

1. read the command before pressing Enter. especially when there’s a * in it. especially when there’s a -r in it.
2. never run rm -rf / (or rm -rf ~, or any rm -rf on a path you’re not 100% sure about). that command tries to delete everything it can reach.

that’s it. follow those two rules and rm stays manageable.

common mistakes

“No such file or directory” on cp or mv. you’re probably not in the folder you think you’re in. pwd first. or give the full path.

rm fails on a folder. plain rm won’t delete a folder — you need rm -r folder (recursive). the simulator above will tell you “is a directory” if you forget the -r.

mv silently overwrites. if new.txt already exists and you run mv old.txt new.txt, the old new.txt is replaced. no warning. if that matters, ls first to check.

you delete the wrong file with a wildcard. you meant rm *.bak but typed rm * (which deletes everything in the folder). always ls the pattern before using it with rm.

what this unlocks

you can now make, copy, rename, and delete files without the help of a file manager. that’s already enough for most day-to-day terminal work.

next up: terminal 103 — pipes, redirects, and finding things. that’s the point where single commands stop being the whole story. you’ll send one command’s output into another, save results to files, and search through a project without clicking folder by folder.