Make install script runnable on Alpine Linux bash. Do not use rsync,tput, etc

install.sh

@@ -2,6 +2,7 @@
 
 set -e
 set -u
+set -o pipefail
 
 is_app_installed() {
   type "$1" &>/dev/null
@@ -11,13 +12,13 @@ REPODIR="$(cd "$(dirname "$0")"; pwd -P)"
 cd "$REPODIR";
 
 if ! is_app_installed tmux; then
-  printf "$(tput setaf 1)WARNING:$(tput sgr0) \"tmux\" command is not found. \
+  printf "WARNING: \"tmux\" command is not found. \
 Install it first\n"
   exit 1
 fi
 
 if [ ! -e "$HOME/.tmux/plugins/tpm" ]; then
-  printf "$(tput setaf 1)WARNING:$(tput sgr0) Cannot found TPM (Tmux Plugin Manager) \
+  printf "WARNING: Cannot found TPM (Tmux Plugin Manager) \
  at default location: \$HOME/.tmux/plugins/tpm.\n"
   git clone https://github.com/tmux-plugins/tpm ~/.tmux/plugins/tpm
 fi
@@ -26,16 +27,17 @@ if [ -e "$HOME/.tmux.conf" ]; then
   printf "Found existing .tmux.conf in your \$HOME directory. Will create a backup at $HOME/.tmux.conf.bak\n"
 fi
 
-rsync -aq ./tmux/ "$HOME"/.tmux
-
-ln -sf --backup --suffix=.bak .tmux/tmux.conf "$HOME"/.tmux.conf;
+cp -f "$HOME/.tmux.conf" "$HOME/.tmux.conf.bak" 2>/dev/null || true
+cp -a ./tmux/. "$HOME"/.tmux/
+ln -sf .tmux/tmux.conf "$HOME"/.tmux.conf;
 
 # Install TPM plugins.
 # TPM requires running tmux server, as soon as `tmux start-server` does not work
 # create dump __noop session in detached mode, and kill it when plugins are installed
+printf "Install TPM plugins\n"
 tmux new -d -s __noop >/dev/null 2>&1 || true 
 tmux set-environment -g TMUX_PLUGIN_MANAGER_PATH "~/.tmux/plugins"
 "$HOME"/.tmux/plugins/tpm/bin/install_plugins || true
 tmux kill-session -t __noop >/dev/null 2>&1 || true
 
-printf "$(tput setaf 2)OK:$(tput sgr0) Completed\n"
+printf "OK: Completed\n"