title: Linux bash shell set命令 详解


-a  标示已修改的变量,以供输出至环境变量。
-b  使被中止的后台程序立刻回报执行状态。
-C  转向所产生的文件无法覆盖已存在的文件。
-d  Shell预设会用杂凑表记忆使用过的指令,以加速指令的执行。使用-d参数可取消。
-e  若指令传回值不等于0,则立即退出shell。
-f   取消使用通配符。
-h  自动记录函数的所在位置。
-H Shell  可利用"!"加<指令编号>的方式来执行history中记录的指令。
-k  指令所给的参数都会被视为此指令的环境变量。
-l  记录for循环的变量名称。
-m  使用监视模式。
-n  只读取指令,而不实际执行。
-p  启动优先顺序模式。
-P  启动-P参数后,执行指令时,会以实际的文件或目录来取代符号连接。
-t  执行完随后的指令,即退出shell。
-u  当执行时使用到未定义过的变量,则显示错误信息。
-v  显示shell所读取的输入值。
-x  执行指令后,会先显示该指令及所下的参数。
+<参数>  取消某个set曾启动的参数。

    set - Set or unset values of shell options and positional parameters.

    set [--abefhkmnptuvxBCHP] [-o option-name] [arg ...]

    Set or unset values of shell options and positional parameters.

    Change the value of shell attributes and positional parameters, or
    display the names and values of shell variables.

      -a  Mark variables which are modified or created for export.
      -b  Notify of job termination immediately.
      -e  Exit immediately if a command exits with a non-zero status.
      -f  Disable file name generation (globbing).
      -h  Remember the location of commands as they are looked up.
      -k  All assignment arguments are placed in the environment for a
          command, not just those that precede the command name.
      -m  Job control is enabled.
      -n  Read commands but do not execute them.
      -o option-name
          Set the variable corresponding to option-name:
              allexport    same as -a
              braceexpand  same as -B
              emacs        use an emacs-style line editing interface
              errexit      same as -e
              errtrace     same as -E
              functrace    same as -T
              hashall      same as -h
              histexpand   same as -H
              history      enable command history
              ignoreeof    the shell will not exit upon reading EOF
                           allow comments to appear in interactive commands
              keyword      same as -k
              monitor      same as -m
              noclobber    same as -C
              noexec       same as -n
              noglob       same as -f
              nolog        currently accepted but ignored
              notify       same as -b
              nounset      same as -u
              onecmd       same as -t
              physical     same as -P
              pipefail     the return value of a pipeline is the status of
                           the last command to exit with a non-zero status,
                           or zero if no command exited with a non-zero status
              posix        change the behavior of bash where the default
                           operation differs from the Posix standard to
                           match the standard
              privileged   same as -p
              verbose      same as -v
              vi           use a vi-style line editing interface
              xtrace       same as -x
      -p  Turned on whenever the real and effective user ids do not match.
          Disables processing of the $ENV file and importing of shell
          functions.  Turning this option off causes the effective uid and
          gid to be set to the real uid and gid.
      -t  Exit after reading and executing one command.
      -u  Treat unset variables as an error when substituting.
      -v  Print shell input lines as they are read.
      -x  Print commands and their arguments as they are executed.
      -B  the shell will perform brace expansion
      -C  If set, disallow existing regular files to be overwritten
          by redirection of output.
      -E  If set, the ERR trap is inherited by shell functions.
      -H  Enable ! style history substitution.  This flag is on
          by default when the shell is interactive.
      -P  If set, do not follow symbolic links when executing commands
          such as cd which change the current directory.
      -T  If set, the DEBUG trap is inherited by shell functions.
      -   Assign any remaining arguments to the positional parameters.
          The -x and -v options are turned off.

    Using + rather than - causes these flags to be turned off.  The
    flags can also be used upon invocation of the shell.  The current
    set of flags may be found in $-.  The remaining n ARGs are positional
    parameters and are assigned, in order, to $1, $2, .. $n.  If no
    ARGs are given, all shell variables are printed.

    Exit Status:
    Returns success unless an invalid option is given.


    GNU bash, version 4.1.5(1)-release (i486-pc-linux-gnu)
    Copyright (C) 2009 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later