用户使用GDM登录后，怎么运行脚本？

Resolution

• 在会话开始之前和会话结束时，GDM有一系列脚本需要在登录之后运行。

在使用文本console时、像~/.bash_profile一样，/etc/X11/gdm/PreSession/Default可以在用户登录后被运行。

• 在编辑这个文件时，确认添加行都是在“exec”命令后添加的，从而在这之后的任何东西都不会被处理:

  #!/bin/sh
  #
  # Note that any setup should come before the sessreg command as
  # that must be 'exec'ed for the pid to be correct (sessreg uses the
  parent
  # pid)
  #
  # Note that output goes into the .xsession-errors file for easy
  debugging
  #
  PATH="/usr/bin/X11:/usr/X11R6/bin:/opt/X11R6/bin:$PATH:/bin:/usr/bin"
  
  # this is a good place to add custom command lines to be executed
  date > /tmp/last_X_login.txt
  
  gdmwhich () {
  COMMAND="$1"
  OUTPUT=
  IFS=:
  for dir in $PATH
  do
  if test -x "$dir/$COMMAND" ; then
  if test "x$OUTPUT" = "x" ; then
  OUTPUT="$dir/$COMMAND"
  fi
  fi
  done
  unset IFS
  echo "$OUTPUT"
  }
  
  XSETROOT=`gdmwhich xsetroot`
  if [ "x$XSETROOT" != "x" ] ; then
  # Try to snarf the BackgroundColor from the config file
  BACKCOLOR=`grep '^BackgroundColor' /etc/X11/gdm/gdm.conf | sed
  's/^.*=\\(.*\\)$/\\1/'`
  if [ "x$BACKCOLOR" = "x" ]; then
  BACKCOLOR="#76848F"
  fi
  "$XSETROOT" -cursor_name left_ptr -solid "$BACKCOLOR"
  fi
  
  SESSREG=`gdmwhich sessreg`
  if [ "x$SESSREG" != "x" ] ; then
  # some output for easy debugging
  echo "$0: Registering your session with wtmp and utmp"
  echo "$0: running: $SESSREG -a -w /var/log/wtmp -u /var/run/utmp
  -x \\"$X_SERVERS\\" -h \\"$REMOTE_HOST\\" -l \\"$DISPLAY\\" \\"$USER\\""
  
  exec "$SESSREG" -a -w /var/log/wtmp -u /var/run/utmp -x
  "$X_SERVERS" -h "$REMOTE_HOST" -l "$DISPLAY" "$USER"
  # This section will not be read. Do not add scripts here.
  fi
  
  # some output for easy debugging
  echo "$0: could not find the sessreg utility, cannot update wtmp and
  utmp"
  exit 0
  

• /etc/X11/gdm/PostSession/Default可以被编辑从而得到像~/.bash_logout一样的一些东西。

• 虽然脚本可以以root用户运行,但是 $HOME , `$USER以及类似的环境变量会因为用户的登录而被恰当的设定。