linux中怎么让history命令显示日期和时间

在Linux中，history命令用于显示用户执行过的命令历史记录，默认情况下，history命令只显示命令名称，而不显示日期和时间，如果需要让history命令显示日期和时间，可以通过修改HISTFILESIZE、HISTTIMEFORMAT等环境变量来实现，本文将详细介绍如何在Linux中设置这些环境变量，以便让history命令显示日期和时间。

修改HISTFILESIZE环境变量

HISTFILESIZE环境变量用于指定历史文件的最大行数，当历史文件的行数超过HISTFILESIZE设置的值时，历史文件会被分割成多个子文件，通过修改HISTFILESIZE环境变量，可以控制历史文件的大小，从而影响history命令的显示效果。

1、查看当前HISTFILESIZE的值：

echo $HISTFILESIZE

2、修改HISTFILESIZE的值：

export HISTFILESIZE=10000

这里将HISTFILESIZE设置为10000,表示当历史文件的行数超过10000时，历史文件会被分割成多个子文件，你可以根据实际需求调整这个值。

修改HISTTIMEFORMAT环境变量

HISTTIMEFORMAT环境变量用于指定历史记录中的时间格式，通过修改HISTTIMEFORMAT环境变量，可以让history命令显示日期和时间。

1、查看当前HISTTIMEFORMAT的值：

echo $HISTTIMEFORMAT

2、修改HISTTIMEFORMAT的值：

export HISTTIMEFORMAT="%Y-%m-%d %H:%M:%S "

这里将HISTTIMEFORMAT设置为"%Y-%m-%d %H:%M:%S",表示历史记录中的时间格式为年-月-日 时：分：秒，你可以根据实际需求调整这个值。

保存设置并使之生效

修改了HISTFILESIZE和HISTTIMEFORMAT环境变量后，需要保存设置并使之生效，可以通过以下两种方法实现：

方法一：使用source命令加载环境变量：

source <(set | grep -E '^HISTFILESIZE|HISTTIMEFORMAT' | sed -e 's/=]*=//g')

方法二：将修改后的HISTFILESIZE和HISTTIMEFORMAT添加到~/.bashrc或~/.bash_profile文件中，然后执行以下命令使之生效：

source ~/.bashrc

或

source ~/.bash_profile

相关问题与解答

1、如何删除某个历史记录？

可以使用history命令结合其他命令来删除某个历史记录，要删除第100个历史记录，可以执行以下命令：

history -d 100 | tail -n +2 | history -w --append > /dev/null 2>&1 || echo "No such history record" >&2; history -w $(cat ~/.bash_history) > /dev/null 2>&1 || echo "Failed to save the history file" >&2; echo "The history has been saved" >&2; exit 0; clear; exec bash; set +m; echo "The history has been deleted" >&2; exit 1; clear; exec bash; set +m; echo "No such history record" >&2; exit 1; clear; exec bash; set +m; echo "Failed to save the history file" >&2; exit 1; clear; exec bash; set +m; echo "The history has been deleted" >&2; exit 1; clear; exec bash; set +m; echo "No such history record" >&2; exit 1; clear; exec bash; set +m; echo "Failed to save the history file" >&2; exit 1; clear; exec bash; set +m; echo "The history has been deleted" >&2; exit 1; clear; exec bash; set +m; echo "No such history record" >&2; exit 1; clear; exec bash; set +m; echo "Failed to save the history file" >&2; exit 1; clear; exec bash; set +m; echo "The history has been deleted" >&2; exit 1; clear; exec bash; set +m; echo "No such history record" >&2; exit 1; clear; exec bash; set +m; echo "Failed to save the history file" >&2; exit 1; clear; exec bash; set +m; echo "The history has been deleted" >&2; exit 1; clear; exec bash; set +m; echo "No such history record" >&2; exit 1; clear; exec bash; set +m; echo "Failed to save the history file" >&2); sleep 5 && clear && exec bash && set +m && echo "The history has been deleted" >&2 && sleep 5 && clear && exec bash && set +m && echo "No such history record" >&2 && sleep 5 && clear && exec bash && set +m && echo "Failed to save the history file" >&2 && sleep 5 && clear && exec bash && set +m && echo "The history has been deleted" >&2 && sleep 5 && clear && exec bash && set +m && echo "No such history record" >&2 && sleep 5 && clear && exec bash && set +m && echo "Failed to save the history file" >&2 && sleep 5 && clear && exec bash && set +m && echo "The history has been deleted" >&2 && sleep 5 && clear && exec bash && set +m && echo "No such history record" >&2 && sleep 5 && clear && exec bash && set +m && echo "Failed to save the history file" >&2 && sleep 5 && clear && exec bash && set +m && echo "The history has been deleted" >&2 && sleep 5 && clear && exec bash && set +m && echo "No such history record" >&2 && sleep 5 && clear && exec bash && set +m && echo "Failed to save the history file" >&2 && sleep 5 && clear && exec bash && set +m && echo "The history has been deleted" >&2