Installer internals

install.sh is one bash script, written to run on bash 3.2 (macOS) and up, under set -euo pipefail:

• -e stop at the first command that fails (unless the failure is handled)
• -u treat unset variables as errors (catches typos)
• -o pipefail a pipeline fails if any part fails, not just the last

Run order

Everything runs inside main, which is called on the very last line:

main
├── detect_system        SYSTEM, NANO_SHARE, PKG_MGR
├── ask_questions        SHELL_CHOICE, LOCALE  (flags → prompts → defaults)
├── confirm_plan         print plan, "Proceed? [Y/n]"
├── install_nano
├── install_tmux         + TPM, Catppuccin (git clone)
├── ensure_nerd_font     desktops only, chosen font → ~/.local/share/fonts
├── install_kitty        + theme files, ensure_kitty_terminfo
├── install_nvim
├── install_starship
├── ensure_shell_tools   less, bash-completion, notify-send
├── ensure_locale
├── write_locale_conf
├── ensure_zsh           only if SHELL_CHOICE = zsh
├── install_shell_common .aliases, .functions
├── install_zsh          .zshrc, .zshenv, .zprofile
├── install_bash         .bash_profile, .bashrc, .inputrc
└── set_login_shell      chsh

Why main? With curl … | bash, bash runs the script while it’s still downloading. Because only function definitions come before the last line, nothing runs until the whole file has arrived. A cut-off download can’t run half an install, and no command (like apt) can swallow the rest of the script by reading from stdin.

Globals

Variable	Set by	Values
SYSTEM	detect_system	linux, macos-intel, macos-arm
NANO_SHARE	detect_system	nano’s syntax folder for this platform
PKG_MGR	detect_system	apt, dnf, yum, pacman, zypper, apk, brew, or empty
MODE	flags	local or remote
SHELL_CHOICE	flags / ask_questions	zsh, bash, keep
LOCALE	flags / ask_questions	e.g. en_US.UTF-8
FONT_CHOICE	flags / ask_questions	Nerd Font archive name (Hasklig, FiraCode…) or none; always none when not a desktop
NERD_FONTS_VERSION	top of file	pinned Nerd Fonts release to download from
ASSUME_YES	-y	0 / 1
DEFAULT_SHELL, DEFAULT_LOCALE	top of file	defaults for -y and no-terminal runs

On macOS only brew counts as a package manager; on Linux a Linuxbrew install is ignored so system packages go through the distro’s own manager.

Shared helpers

Helper	Job	Rule
fetch_source <path>	returns a local path for a repo file — the checkout in local mode, a downloaded temp copy in remote mode	never use $REPO_DIR directly, so every config works in both modes
backup_if_exists <dest>	moves an existing file to <dest>.bak.<timestamp>	call before every write
install_home_files <files…>	copy + back up a list of files to the same path under $HOME	used by the shell installers
as_root <cmd…>	runs a command directly when root, via sudo otherwise	use for anything touching /etc
pkg_install <pkgs…>	installs through $PKG_MGR; apt-get update once per run; pacman -Syu only on unsynced systems	never call a package manager directly; returns non-zero instead of exiting
has_tty	can we open /dev/tty?
can_prompt	not -y and has_tty	check before asking anything
ask_choice "<q>" <default> <opts…>	numbered menu, result in REPLY_CHOICE	the only way to prompt
normalize_locale	ja_JP / ja_JP.utf8 → ja_JP.UTF-8, or fail
is_desktop	macOS, or $DISPLAY / $WAYLAND_DISPLAY set	gate desktop-only things

Why prompts read from /dev/tty

With curl … | bash, the script itself arrives on stdin. A plain read would take the next line of the script as the answer. /dev/tty is the keyboard directly.

Checking that /dev/tty exists isn’t enough: in Docker it exists but can’t be opened. So has_tty actually opens it:

has_tty() {
    { : </dev/tty; } 2>/dev/null     # ':' does nothing; this only tests the open
}

Why failures warn instead of exit

Under set -e any failing command stops the script. So main runs every step through run_step: if a step fails (no network, a file that couldn’t be downloaded…), it prints a warning and goes on with the next step. At the end the script lists the failed steps and exits with 1, so scripts and CI notice:

Done, but these steps failed: install_tmux install_starship

Each step runs in a subshell, ( set -e; step ), so it still stops at its own first error. It can’t be written as step || warn: bash ignores set -e inside anything on the left of ||, so a broken step would carry on and look successful.

Inside a step, optional parts like package installs use pkg_install … || echo "warning: …", so a missing package doesn’t fail the whole step.

Platform differences

Paths that differ between systems are rewritten while copying, not kept as separate files. Example: nanorc contains the Linux path /usr/share/nano; install_nano swaps in $NANO_SHARE with sed. Add a new global in detect_system for any new platform-specific path.

Package names by system

Purpose	apt	dnf / yum	pacman	zypper	apk
notify-send	libnotify-bin	libnotify	libnotify	libnotify-tools	libnotify
kitty terminfo	kitty-terminfo	kitty-terminfo	kitty-terminfo	kitty-terminfo	kitty-terminfo
locales	locales + locale-gen	glibc-langpack-<lang>	locale-gen	glibc-locale	—
chsh	(built in)	util-linux-user	(built in)	(built in)	shadow