fixes and improvements

tmux/.is_vim.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+# Usage: is_vim.sh <tty>
+#   tty: Specify tty to check for vim process.
+tty=$1
+
+# Construct process tree.
+children=();
+pids=( $(ps -o pid= -t $tty) )
+
+while read -r pid ppid
+do
+  [[ -n pid && pid -ne ppid ]] && children[ppid]+=" $pid"
+done <<< "$(ps -Ao pid=,ppid=)"
+
+# Get all descendant pids of processes in $tty with BFS
+idx=0
+while (( ${#pids[@]} > idx ))
+do
+  pid=${pids[idx++]}
+  pids+=( ${children[pid]-} )
+done
+
+# Check whether any child pids are vim
+ps -o state=,comm= -p "${pids[@]}" | grep -iqE '^[^TXZ ]+ +(\\S+\\/)?g?(view|n?vim?x?)(diff)?$'
+exit $?