terminal: Create module to consolidate term utils

Terminal application, a variety of shell configurations, terminal file
and session management all consolidated in one place.

terminal/.config/sh/alias.d/tmux.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env sh
+
+exist() { type "$1" >/dev/null 2>&1; }
+
+# alias tmux to follow xdg-specification
+# shellcheck disable=2139
+alias tmux="tmux -f ${XDG_CONFIG_HOME:-$HOME/.config}/tmux/tmux.conf"
+
+# fzf
+if exist fzf; then
+    # fzf select a tmux session to connect to, with pane preview
+    alias tm='_fzf_tmux_attach_start_session'
+    alias tl=tm
+else
+    alias tm='tmux_attach_start'
+    # show a list of running tmux sessions
+    alias tl='tmux list-sessions -F "#{session_name}" 2>/dev/null '
+fi
+
+_fzf_tmux_list_sessions() {
+    tmux list-sessions -F "#{session_name}" 2>/dev/null | fzf \
+        --layout=reverse \
+        --height=50% \
+        --border \
+        --prompt="Session> " \
+        --preview="tmux_pane_tree {}" \
+        --preview-window=right:80% \
+        --print-query
+}
+
+_fzf_tmux_attach_start_session() {
+    if [ -z "$1" ]; then
+        result=$(_fzf_tmux_list_sessions)
+        case "$?" in
+        0)
+            # found a session, attaching
+            tmux_attach_start "$(echo "$result" | tail --lines=1)"
+            ;;
+        1)
+            # did not find a session, creating
+            result=$(echo "$result" | head --lines=1)
+            # if . was only thing entered, create one for current dir
+            if [ "$result" = "." ]; then
+                tmux_attach_start
+                # create for query name
+            else
+                tmux_attach_start "$result"
+            fi
+            ;;
+        esac
+    else
+        tmux_attach_start "$1"
+    fi
+}
+
+unset choice
+unset -f exist