Enable installing plugins via cli executable

bin/install_plugins

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+SCRIPTS_DIR="$CURRENT_DIR/../scripts"
+
+main() {
+	"$SCRIPTS_DIR/install_plugins.sh" # has correct exit code
+}
+main

bindings/install_plugins

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+SCRIPTS_DIR="$CURRENT_DIR/../scripts"
+
+source "$SCRIPTS_DIR/shared_functions.sh"
+
+main() {
+	reload_tmux_environment
+	"$SCRIPTS_DIR/install_plugins.sh" --tmux-echo >/dev/null 2>&1
+	reload_tmux_environment
+	end_message
+}
+main

scripts/install_plugins.sh

@@ -4,9 +4,36 @@ CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
 source "$CURRENT_DIR/shared_functions.sh"
 
+TMUX_ECHO_FLAG="$1"
+
+# True if invoked as tmux mapping or tmux command,
+# false if invoked via command line wrapper from `bin/` directory.
+use_tmux_echo() {
+	[ "$TMUX_ECHO_FLAG" == "--tmux-echo" ]
+}
+
+if use_tmux_echo; then
+	# use tmux specific echo-ing
+	echo_ok() {
+		echo_message "$*"
+	}
+
+	echo_err() {
+		echo_message "$*"
+	}
+else
+	echo_ok() {
+		echo "$*"
+	}
+
+	echo_err() {
+		fail_helper "$*"
+	}
+fi
+
 clone() {
-	local plugin=$1
-	cd $SHARED_TPM_PATH &&
+	local plugin="$1"
+	cd "$SHARED_TPM_PATH" &&
 		GIT_TERMINAL_PROMPT=0 git clone --recursive $plugin
 }
 
@@ -14,25 +41,23 @@ clone() {
 # 1. plugin name directly - works if it's a valid git url
 # 2. expands the plugin name to point to a github repo and tries cloning again
 clone_plugin() {
-	local plugin=$1
+	local plugin="$1"
 	clone "$plugin" ||
 		clone "https://git::@github.com/$plugin"
 }
 
-# pull new changes or clone plugin
+# clone plugin and produce output
 install_plugin() {
 	local plugin="$1"
 	local plugin_name="$(shared_plugin_name "$plugin")"
 
 	if plugin_already_installed "$plugin"; then
-		# plugin is already installed
-		echo_message "Already installed \"$plugin_name\""
+		echo_ok "Already installed \"$plugin_name\""
 	else
-		# plugin wasn't cloned so far - clone it
-		echo_message "Installing \"$plugin_name\""
+		echo_ok "Installing \"$plugin_name\""
 		clone_plugin "$plugin" &&
-			echo_message "  \"$plugin_name\" download success" ||
-			echo_message "  \"$plugin_name\" download fail"
+			echo_ok "  \"$plugin_name\" download success" ||
+			echo_err "  \"$plugin_name\" download fail"
 	fi
 }
 
@@ -50,12 +75,10 @@ verify_tpm_path_permissions() {
 }
 
 main() {
-	reload_tmux_environment
 	shared_set_tpm_path_constant
 	ensure_tpm_path_exists
 	verify_tpm_path_permissions
 	install_plugins
-	reload_tmux_environment
-	end_message
+	exit_value_helper
 }
 main

scripts/shared_functions.sh

@@ -6,7 +6,7 @@ SHARED_TPM_PATH=""
 
 # sets a "global variable" for the current file
 shared_set_tpm_path_constant() {
-	local string_path="$(tmux show-environment -g TMUX_PLUGIN_MANAGER_PATH | cut -f2 -d=)/"
+	local string_path="$(tmux start-server\; show-environment -g TMUX_PLUGIN_MANAGER_PATH | cut -f2 -d=)/"
 	# manually expanding tilde or `$HOME` variable.
 	string_path="${string_path/#\~/$HOME}"
 	SHARED_TPM_PATH="${string_path/#\$HOME/$HOME}"
@@ -18,7 +18,7 @@ _tmux_conf_contents() {
 
 shared_get_tpm_plugins_list() {
 	# DEPRECATED: lists plugins from @tpm_plugins option
-	echo "$(tmux show-option -gqv "$tpm_plugins_variable_name")"
+	echo "$(tmux start-server\; show-option -gqv "$tpm_plugins_variable_name")"
 
 	# read set -g @plugin "tmux-plugins/tmux-example-plugin" entries
 	_tmux_conf_contents |
@@ -96,3 +96,17 @@ display_message() {
 ensure_tpm_path_exists() {
 	mkdir -p "$SHARED_TPM_PATH"
 }
+
+fail_helper() {
+	local message="$1"
+	echo "$message" >&2
+	FAIL="true"
+}
+
+exit_value_helper() {
+	if [ "$FAIL" == "true" ]; then
+		exit 1
+	else
+		exit 0
+	fi
+}

tpm

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+BINDINGS_DIR="$CURRENT_DIR/bindings"
 
 SUPPORTED_TMUX_VERSION="1.9"
 
@@ -31,7 +32,7 @@ source_plugins() {
 # prefix + alt + u - remove unused TPM plugins and reloads TMUX environment
 set_tpm_key_bindings() {
 	local install_key=$(get_tmux_option "$install_key_option" "$default_install_key")
-	tmux bind-key "$install_key" run-shell "$CURRENT_DIR/scripts/install_plugins.sh >/dev/null 2>&1"
+	tmux bind-key "$install_key" run-shell "$BINDINGS_DIR/install_plugins"
 
 	local update_key=$(get_tmux_option "$update_key_option" "$default_update_key")
 	tmux bind-key "$update_key" run-shell "$CURRENT_DIR/scripts/update_plugin_prompt.sh"