How to set the default text editor in Zsh

A Zsh terminal passes exported editor variables to programs launched from that shell, so commands such as crontab -e, sudoedit, and git commit open the editor selected for that account. Setting the editor in ~/.zshrc keeps interactive Zsh sessions from falling back to a program chosen separately by each tool.

$VISUAL is the first editor preference many terminal programs check, while $EDITOR remains the fallback for tools that only honor the older variable. Export both variables to the same editor command unless a graphical editor and a terminal editor need separate choices.

Interactive Zsh reads the user's rc file after the global startup files; for a normal home-directory setup that file is ~/.zshrc. If $ZDOTDIR is set, put the same lines in $ZDOTDIR/.zshrc instead, and keep Debian or Ubuntu's /usr/bin/editor alternative separate from these shell variables.

Steps to set the default text editor in Zsh:

Check the editor variables in the active Zsh session.
```
$ printf 'VISUAL=%s\nEDITOR=%s\n' "${VISUAL-}" "${EDITOR-}"
VISUAL=
EDITOR=
```
An empty value means no editor preference is exported from the current shell.
Confirm the editor command to export.
```
$ command -v nano
/usr/bin/nano
```
Replace nano with vim, nvim, emacs, micro, or another editor command that exists on the system.
Open the current user's Zsh rc file.
```
$ nano ~/.zshrc
```
Use $ZDOTDIR/.zshrc instead when the account sets ZDOTDIR to store Zsh startup files outside the home directory.
Add or update both editor exports near the other interactive shell settings.
~/.zshrc
```
export VISUAL=/usr/bin/nano
export EDITOR=/usr/bin/nano
```
If the file already assigns VISUAL or EDITOR, replace the old lines instead of leaving conflicting values later in the same file.

Quote the value when the editor command includes arguments, for example export VISUAL="code --wait".
Check the edited rc file for syntax errors.
```
$ zsh -n ~/.zshrc
```
No output from zsh -n means Zsh parsed the file without finding a syntax error. Use $ZDOTDIR/.zshrc instead when that is the file you edited.
Reload the same rc file in the current Zsh terminal.
```
$ source ~/.zshrc
```
Use source "$ZDOTDIR/.zshrc" when the startup file lives under a custom ZDOTDIR directory.

Verify that the current shell exports both editor variables.

$ printf 'VISUAL=%s\nEDITOR=%s\n' "$VISUAL" "$EDITOR"
VISUAL=/usr/bin/nano
EDITOR=/usr/bin/nano

Start a new interactive Zsh process and confirm the same values load automatically.
```
$ zsh -ic 'printf "VISUAL=%s\nEDITOR=%s\n" "$VISUAL" "$EDITOR"'
VISUAL=/usr/bin/nano
EDITOR=/usr/bin/nano
```
A matching output confirms that ~/.zshrc applies the editor choice to new interactive Zsh sessions.
Run a command that opens an editor from the shell environment.
```
$ crontab -e
```
crontab -e, sudoedit, and many other command-line tools read $VISUAL or $EDITOR when choosing which editor to launch.

On Debian and Ubuntu, sudo update-alternatives --config editor changes the generic /usr/bin/editor link. That setting is separate from the Zsh variables above.