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# Changing files
The command line · Using a shell
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## Today
**We are learning to** mkdir makes a folder, cp copies, mv moves or renames, rm deletes and echo … > saves text into a file. rm is for good: there is no recycle bin in a shell, so look before you delete.
- I can make folders and copy, move and rename files.
- I can delete files and folders, knowing it is for good.
- I can save text into a file.
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## Why it matters
> On your laptop, deleted files go to the bin. In a shell, rm means gone. Ready?
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💬 Discussion
## Predict
**You type rm notes.txt. Where is notes.txt now?**
- Gone for good: a shell has no recycle bin
- Still there until you restart
- In the recycle bin
- In a hidden folder called .trash
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✍️ Activity
## Try it
{{embed: https://studio.learningwaypoints.com/tutorials/_playground-board/index.html?id=deck%2Fsystems%2Fshell%2Fchanging%2Fstep-2&code=widget%3A+shell%0Atree%3A+on%0Aexists%3A+%2Fhome%2Fsam%2Fold%2Fnotes.txt%0Agone%3A+%2Fhome%2Fsam%2Fnotes.txt%0A&fresh=1}}
[Open this step in the tutorial](https://studio.learningwaypoints.com/tutorials/systems/shell/changing/?full=step-2#step-2)
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✅ Check
## What happened?
* Gone. rm deletes straight away; the bin on your laptop is something the desktop adds, not the operating system.
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💬 Discussion
## Five commands that change things
Now compare cp and mv.
$$\text{mkdir old}$$
1) $\text{cp notes.txt old}$ — Copy: notes.txt stays, and old/notes.txt is a second copy.
2) $\text{mv notes.txt old}$ — Move: notes.txt leaves here and goes into old. Also renames: mv a.txt b.txt.
3) $\text{rm notes.txt}$ — Delete, for good. rm -r deletes a folder and everything in it.
4) $\text{echo hi > hello.txt}$ — Save some text into a file (> replaces it; >> adds to the end).
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✅ Check
## Five commands that change things
**You type mv pets.txt photos. Then ls in your home folder. Is pets.txt there?**
- Yes, and there's another in photos
- It's deleted
- No: mv moved it into photos
- Yes: mv makes a copy
* Answer: No: mv moved it into photos
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✅ Check
## Find the mistake
**Sam deletes a file. Click the line where it first goes wrong.**
```
1 Sam types rm notes.txt.
2 ls no longer shows notes.txt.
3 The file is in the recycle bin, like on a laptop.
4 So Sam can get it back later if needed.
```
* Answer: line 3
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✅ Check
## Renaming
**How do you rename notes.txt to todo.txt?**
- rename notes.txt
- mv notes.txt todo.txt
- cp notes.txt todo.txt
- cd notes.txt todo.txt
* Answer: mv notes.txt todo.txt
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✍️ Activity
## Vary: one change each
- **Rename:**
- **Make a file:**
- **Remove a folder:**
[Open this step](https://studio.learningwaypoints.com/tutorials/systems/shell/changing/?full=step-4#step-4)
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✅ Check
## Back up first
**You want to try editing report.txt but keep the original safe. What first?**
- mv report.txt report-backup.txt
- rm report.txt
- cp report.txt report-backup.txt
- mkdir report.txt
* Answer: cp report.txt report-backup.txt
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✅ Check
## Replace or add
**echo hi > notes.txt. What happens to what was in notes.txt?**
- Nothing: it saves to a new file
- hi is added to the end
- It's replaced by hi
- An error
* Answer: It's replaced by hi
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✅ Check
## Review: hidden
**Review: how do you see hidden files?**
- ls
- cd .hidden
- ls -a
- cat -a
* Answer: ls -a
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✍️ Activity
## Make: tidy up
Then: which of today's commands would you be most careful with, and why?
[Open this step](https://studio.learningwaypoints.com/tutorials/systems/shell/changing/?full=step-6#step-6)
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✅ Check
## Exit ticket
**What is the difference between cp notes.txt old and mv notes.txt old? Which is safer before deleting?**
* cp leaves the original and makes a copy in old; mv moves it. cp is safer.