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