zsh 中的extended_history 有什么作用？

Question

我看到了选项 extended_history 并看到它在 zsh中的Per-directory history 中使用，但还没有真正理解 extended_history 实际上做了什么？

什么信息。将在 zsh_history 中可用，否则如果未设置此选项则不会。

从http://zsh.sourceforge.net/Doc/Release/Options.html#Options它说 -

EXTENDED_HISTORY <C>

    Save each command’s beginning timestamp (in seconds since the epoch) and the duration (in seconds) to the history file. The format of this prefixed data is:

    ‘: <beginning time>:<elapsed seconds>;<command>’. 

但至少在运行历史命令时我看不到它有任何好处 -

 shirish@debian ~ % history | grep tail -5
      601* exit
      602* history
      603* exit
      604  cd
      605  cat ~/.zsh/.zshrc
      606   tail -5 history

这是我~/.zsh/.zshrc的设置方式-

shirish@debian ~ % cat ~/.zsh/.zshrc
# Lines configured by zsh-newuser-install
HISTFILE=~/.zsh//.histfile
HISTSIZE=1000
SAVEHIST=100000
setopt inc_append_history autocd nomatch notify share_history extended_history
bindkey -e
# End of lines configured by zsh-newuser-install

# display how long all tasks over 10 seconds take
export REPORTTIME=10

# The following lines were added by compinstall
zstyle :compinstall filename '/home/shirish/.zsh//.zshrc'

autoload -Uz compinit promptinit
compinit
promptinit
# End of lines added by compinstall

prompt adam1

设置选项后或将其取出后我都没有看到任何区别，没有任何有意义的区别。

shirish@debian ~ % cat ~/.zsh/.zshrc | grep setopt
setopt inc_append_history autocd nomatch notify share_history extended_history
shirish@debian ~ % source ~/.zsh/.zshrc           
shirish@debian ~ % history -E                     
  337  11.1.2018 23:33  history | grep apg
  338  11.1.2018 23:33  man apg
  339  11.1.2018 23:33  cd
  340  11.1.2018 23:33  apg -a 1 -M n -n 3 -m 20
  341  11.1.2018 23:33  apg -a 1 -M SNCL -n 3 -m 20
  342  11.1.2018 23:33  history 
  343  11.1.2018 23:33  history -E
  344  11.1.2018 23:33  leafpad ~/.zsh/.zshrc
  345  11.1.2018 23:33  cat ~/.zsh/.zshrc
  346  11.1.2018 23:33  source ~/.zsh/.zshrc
  347  11.1.2018 23:33  history -E
  348  11.1.2018 23:33  exit
  349  11.1.2018 23:33  history -E
  350  11.1.2018 23:34  leafpad ~/.zsh/.zshrc
  351  11.1.2018 23:35  cat ~/.zsh/.zshrc | grep setopt
  352  11.1.2018 23:35  source ~/.zsh/.zshrc
shirish@debian ~ % leafpad ~/.zsh/.zshrc          
shirish@debian ~ % source ~/.zsh/.zshrc 
shirish@debian ~ % history -E           
  340  11.1.2018 23:33  apg -a 1 -M n -n 3 -m 20
  341  11.1.2018 23:33  apg -a 1 -M SNCL -n 3 -m 20
  342  11.1.2018 23:33  history 
  343  11.1.2018 23:33  history -E
  344  11.1.2018 23:33  leafpad ~/.zsh/.zshrc
  345  11.1.2018 23:33  cat ~/.zsh/.zshrc
  346  11.1.2018 23:33  source ~/.zsh/.zshrc
  347  11.1.2018 23:33  history -E
  348  11.1.2018 23:33  exit
  349  11.1.2018 23:33  history -E
  350  11.1.2018 23:34  leafpad ~/.zsh/.zshrc
  351  11.1.2018 23:35  cat ~/.zsh/.zshrc | grep setopt
  352  11.1.2018 23:35  source ~/.zsh/.zshrc
  353  11.1.2018 23:35  history -E
  354  11.1.2018 23:36  leafpad ~/.zsh/.zshrc
  355  11.1.2018 23:36  source ~/.zsh/.zshrc
shirish@debian ~ % cat ~/.zsh/.zshrc | grep setopt
setopt inc_append_history autocd nomatch notify share_history

可以看出，似乎没有任何区别。

% zsh --version
zsh 5.4.2 (x86_64-debian-linux-gnu)

Answer 1

无论选项如何，输出history -E始终相同EXTENDED_HISTORY。命令的持续时间直接存储在历史文件中（只需检查该文件即可查看值）。

然而，另一个问题是有一些选项可以覆盖此行为。您可以通过运行类似的命令来测试它是否正常工作sleep 3，这应该会产生如下所示的条目：

pol@host ~ $ sleep 3
pol@host ~ $ tail -1 ${HISTFILE}
: 1530663493:3;sleep 3
pol@host ~ $ setopt | grep hist
extendedhistory
histignoredups
incappendhistorytime

您可以看到“持续时间”值为 3。如果它不是 3，则很可能您设置了另一个阻止EXTENDED_HISTORY工作的选项。这些包括SHARED_HISTORY和INC_APPEND_HISTORY。如果您需要前者，那么您就不走运了。对于后一种情况，INC_APPEND_HISTORY_TIME如果您还想拥有EXTENDED_HISTORY值（如我上面所述），则可以使用另一种替代方法。