allexport –a （set -a 同 set -o allexport） Causes set variables to be automatically exported. 变量设置后自动export
bgnice Runs background jobs with a lower priority. 以比较低的优先级运行后台工作。
emacs For command-line editing, uses the emacs built-in editor. 命令行编辑器，使用emacs内置编辑器（一般我都用vi）
errexit –e （set -e 同 set -o errexit） If a command returns a nonzero exit status (fails), executes the ERR trap, if set, and exits. Not set when reading initialization files. 如果一个命令产生非0退出状态则退出，退出前执行ERR陷阱
gmacs For command-line editing, uses the gmacs built-in editor. 使用gmacs编辑器
ignoreeof Prevents logout with ^D; must type exit to exit the shell. 不处理EOF信号，必须键入exit方可退出shell
markdirs Puts a trailing backslash (/) on directory names when filename expansion is used. 添加/到目录名 （不是很清楚，请补充）
noclobber Protects files from being overwritten when redirection is used. 阻止通过重定向“>”来修改文件，而用“ >| ”去修改
noexec –n Reads commands, but does not execute them. Used to check the syntax of scripts. Not on when running interactively. 只读命令但不执行，通常在检查语法时有用，交互状态失效。
noglob –f Disables pathname expansion; that is, turns off wildcards. 忽略文件名元字符 （例如，* ? [ ] ）
nolog Does not store function definitions in the history file. 在历史文件中不保留函数定义
notify Notifies user when background job finishes. 后台作业终止时打印消息
nounset Displays an error when expanding a variable that has not been set. 在替换时，将清除变量视为错误 （不明白，请补充）
privileged –p When set, the shell does not read the .profile or ENV file; used with setuid scripts. 作为一个特权用户来执行，不处理.profile 或 ENV文件。
trackall Enables alias tracking. 创建跟踪别名。
verbose –v Turns on the verbose mode for debugging. 在读的时候，显示每一行shell命令行。
vi For command-line editing, uses the vi built-in editor. vi编辑器
xtrace –x Turns on the echo mode for debugging. 在调试时打开echo模式
