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

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.

-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.

# 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:

set +o history

To re-enable recording, use:

set -o history

The commands have no output

Interactive Mode Commands

Flag Description

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.

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

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

!!

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

Command Description

Command	Description
`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.

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:

export HISTTIMEFORMAT="<DateTime_Format>"

Available Date Time Formats Description

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).

%d

Day.

%m

Month.

%y

Year.

%H

Hour.

%M

Minutes.

%S

Seconds.