> For the complete documentation index, see [llms.txt](https://thamizhiniyancs.gitbook.io/cheatsheets/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://thamizhiniyancs.gitbook.io/cheatsheets/linux/knowing-about-files-commands/history.md). # history history linux command cheatsheet by Thamizhiniyan C S ## Introduction This command is used to display the history list with line numbers. *** ## Syntax `history [-c] [-d offset] [n] or history -anrw [filename] or history -ps arg [arg...]` *** ## Important Flags | Flag | Description | | ----------- | ---------------------------------------------------------------------------------------------------------- | | `-c` | Clear the history list by deleting all of the entries. | | `-d offset` | Delete the history entry at position OFFSET. Negative offsets count back from the end of the history list. | | `-a` | Append history lines from this session to the history file. | | `-n` | Read all history lines not already read from the history file and append them to the history list. | | `-r` | Read the history file and append the contents to the history list. | | `-w` | Write the current history to the history file. | | `-p` | Perform history expansion on each ARG and display the result without storing it in the history list. | | `-s` | Append the ARGs to the history list as a single entry. | *** ## Executing Command without making an entry in history Executing a command with space character " " as a prefix will get the job done. ```bash # The following command won't make an entry in history since it is prefixed # with a space character echo "Some Kinda API Key" ``` ## Disabling and Enabling history To prevent recording commands in the history list, temporarily disable recording by using: ```bash set +o history ``` To re-enable recording, use: ```bash set -o history ``` The commands have no output ## Interactive Mode Commands | Flag | Description | | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `ctrl-P` | Move to the previous history entry. This is the same action as the up arrow. | | `ctrl-N` | Move to the next history entry. This is the same action as the down arrow. | | `alt-<` | Move to the beginning (top) of the history list. | | `alt->` | Move to the end (bottom) of the history list, i.e., the current command line. | | `ctrl-R` | Reverse incremental search. This searches incrementally from the current command line up the history list. | | `alt-P` | Reverse search, non-incremental. With this key, type in the search string and press enter before the search is performed. | | `alt-N` | Forward search, non-incremental. | | `ctrl-O` | Execute the current item in the history list and advance to the next one. This is handy if you are trying to re-execute a sequence of commands in the history list. | *** ## Additional Features of history | Flag | Description | | ----------------------------- | ------------------------------------------------------------------------------------------------------------ | | `!!` | Repeat the last command. It is probably easier to press the up arrow and enter. | | `![number]` | Repeat history list item number. | | `![number]:p` | Displays the command associated with event number without executing it. | | `!-[number]` | Add a dash (-) before the command number to run a specific command from the end of the list. | | `![string]` | Repeat last history list item starting with string. | | `!?[string]` | Repeat last history list item containing string. | | `^[old string]^[new string]^` | If you made a typo in a previous command, change it using this syntax. You can find a detailed example below | *** ## Examples
CommandDescription
history
Displays the command history.
history 5
Shows the last 5 commands from the command history.
!1997
Reruns the command with event number 1997.
!1997:p
Displays the command associated with event number 1997 without executing it.
!-7
To reuse the seventh last command
history | grep chpasswd
Filters and displays only the commands containing the term “chpasswd.”
!!
Reruns the last executed command.
!command_starting_string
Executes the latest command starting with “command_starting_string.”
history -d 1996
Removes the command with event number 1996 from history.
history -c
Clears the entire command history.
history | tail
Displays the last 10 commands from the history.
*** ### Customizing history output to show datetime stamps Add the following line to the `.bashrc` file: ```bash export HISTTIMEFORMAT="" ``` | Available Date Time Formats | Description | | --------------------------- | ----------------------------------------------------- | | `%d` | Day. | | `%m` | Month. | | `%y` | Year. | | `%H` | Hour. | | `%M` | Minutes. | | `%S` | Seconds. | | `%F` | Full date (Y-M-D format). | | `%T` | Time (H:M:S format). | | `%c` | Complete date and timestamp (Day-D-M-Y H:M:S format). | For example, To view the complete date and timestamp for each command in history, use the following format: ```bash export HISTTIMEFORMAT="%c " ```
Now save the file and run the command `source .bashrc` or open a new terminal and run the history command to see the DateTime stamps. *** ### Fixing Typos in Previous Command If you made a typo in a previous command, use the following syntax to fix it: ```bash ^[old_string]^[new_string]^ ```
*** ## References {% embed url="" %} {% embed url="" %}