☰

为什么 bash 命令手册中没有 -e 选项？

tag-icon • tag-icon bash man
为什么 bash 命令手册中没有 -e 选项？

我对 bash 手册中缺少的 -e 选项有点困惑。man bash

但它正在使用像 : 这样的脚本 shebang #!/bin/bash -e，当然它是在help set.

为什么 bash 手册的选项中没有列出它？

答案1

在手册的开头就隐含地提到了这一点：

选项内置命令
描述中记录的所有单字符 shell 选项set（包括-o）都可以在调用 shell 时用作选项。 [...]

然后，您需要set在手册中进一步查找内置命令，help set在交互式 shell 会话中使用（正如您在问题中提到的那样），或者以某种适当的方式访问较长的参考手册（例如，通过info bash set在系统上使用命令）这是可行的）。

答案2

它位于 bash(1) 手册页中set。在某些系统上，包括基于 Debian 的系统，您还会发现 bash-builtins(7) 甚至builtins(7) 手册页，其中仅涵盖该 shell 的内置命令，在其中可能更容易找到信息。

...

  -e      Exit immediately if a pipeline (which may consist  of  a
          single  simple  command),  a list, or a compound command
          (see SHELL GRAMMAR above), exits with a non-zero status.
          The  shell  does  not  exit if the command that fails is
          part of the command list immediately following  a  while
          or  until  keyword, part of the test following the if or
          elif reserved words, part of any command executed  in  a
          &&  or || list except the command following the final &&
          or ||, any command in a pipeline but the last, or if the
          command's  return  value is being inverted with !.  If a
          compound command other than a subshell  returns  a  non-
          zero  status because a command failed while -e was being
          ignored, the shell does not exit.  A  trap  on  ERR,  if
          set,  is  executed  before the shell exits.  This option
          applies to the shell environment and each subshell envi‐
          ronment  separately  (see  COMMAND EXECUTION ENVIRONMENT
          above), and may cause subshells to exit before executing
          all the commands in the subshell.

          If  a  compound  command or shell function executes in a
          context where -e is being ignored, none of the  commands
          executed  within  the  compound command or function body
          will be affected by the -e setting, even if  -e  is  set
          and  a  command returns a failure status.  If a compound
          command or shell function sets -e while executing  in  a
          context  where -e is ignored, that setting will not have
          any effect until the compound  command  or  the  command
          containing the function call completes.

...

  errexit Same as -e.

...

相关内容