Where is the hosts file on Mac, Windows, and Linux?

You need to open the hosts file. You already know why. You just cannot remember the path. Here it is for each OS, plus how to open it without fighting permissions.

Paths

On Unix systems /etc/hosts is often a symlink into the real file. Edit the path above. Do not hunt for a second copy in your home folder.

Open it on macOS

Terminal:

sudo nano /etc/hosts

Or open it in your editor with elevated rights:

sudo code /etc/hosts
# or
sudo vim /etc/hosts

Save, then flush DNS:

sudo dscacheutil -flushcache ; sudo killall -HUP mDNSResponder

Finder will not let you edit /etc casually. Use the terminal or an editor launched with sudo.

Open it on Windows

• Open Notepad as Administrator
• File → Open
• Go to C:\Windows\System32\drivers\etc\
• Change the file type filter to All Files
• Open hosts

Without admin rights Windows will open the file but refuse to save.

Then flush DNS:

ipconfig /flushdns

Open it on Linux

sudo nano /etc/hosts
# or
sudo vim /etc/hosts

Flush depends on the stack. Common options:

sudo resolvectl flush-caches
# or
sudo systemd-resolve --flush-caches

What a normal line looks like

127.0.0.1       localhost
127.0.0.1       myapp.test
# 203.0.113.10  staging.example.com

Rules that save time

• IP first, hostname second
• Spaces or tabs both work
• # comments out the rest of the line
• One hostname per line is easier to read than a long list

Quick check after editing

macOS / Linux:

ping -c 1 myapp.test
# or
getent hosts myapp.test

Windows:

ping myapp.test

If the IP in the reply is wrong, the hosts line did not apply yet. Flush DNS and try again before changing the app.

Common mistakes

• Editing a copy in Downloads instead of the system file
• Saving without admin rights (Windows especially)
• Leaving a # in front of the line you meant to enable
• Forgetting the DNS flush
• Using a real public TLD like .com for local names when .test would avoid surprises

Bookmark the path for your OS. You will need it again. If you switch hosts a lot, a small desktop manager helps keep profiles and DNS flush in one place: Locahl.