History command

`history` - GNU History Library

The history command in Linux is a shell built-in (typically in bash) that displays the command history of your current session. It shows a list of previously executed commands, allowing you to review, reuse, or manage them.

Note: history is tied to your shell (usually bash), stored in ~/.bash_history, and requires no special privileges beyond your own session.

Usage: history [options] [n]

n: Optional number of recent commands to display.
options: Flags to modify behavior (e.g., clear, delete).

Common Options

Option	Description
`-c`	Clear the current history list
`-d n`	Delete command number `n`
`-w`	Write current history to file
`-r`	Read history file into current session
`-a`	Append current session to history file

Examples

Basic Usage

Run history to see all commands executed in your current shell session.
```
history
```
- Output (example):
```
  1  ls -l
  2  cd /home/user
  3  cat file.txt
  4  history
```
- Each line has a number (command ID) and the command itself.
Limiting Output

Specify a number to show only the last n commands.
```
history 3
```
- Output:
```
  2  cd /home/user
  3  cat file.txt
  4  history
```
- Shows the last 3 commands.
Reusing Commands

Use !n to re-run a command by its history number.
```
!3
```
- Executes cat file.txt (if 3 was that command).
Last Command:
```
!!
```
- Repeats the most recent command.
Searching History

Press Ctrl+R in the terminal to search interactively.
- Type Ctrl+R, then cat:
```
(reverse-i-search)`cat`: cat file.txt
```
- Press Enter to run, or Ctrl+R again to cycle through matches.
Alternatively, use history | grep:
```
history | grep "cd"
```
- Finds commands containing "cd".
Clearing History

Use -c to erase the current session’s history.
```
history -c
```
- Clears the in-memory history (doesn’t affect ~/.bash_history until logout).
Clear and File:
```
history -c && history -w
```
- Clears memory and overwrites ~/.bash_history with an empty list.
Writing to File

Use -w to save the current session’s history to ~/.bash_history.
```
history -w
```
- Updates the history file immediately (normally done on logout).
Deleting Specific Commands

Remove a command by its number with -d.
```
history -d 2
```
- Deletes command number 2 from the history.
- Check: history shows updated list.

To get help related to the `history` command use `--help` option

$ history --help
history: history [-c] [-d offset] [n] or history -anrw [filename] or history -ps arg [arg...]
    Display or manipulate the history list.

    Display the history list with line numbers, prefixing each modified
    entry with a `*'.  An argument of N lists only the last N entries.

    Options:
      -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

    If FILENAME is given, it is used as the history file.  Otherwise,
    if HISTFILE has a value, that is used, else ~/.bash_history.

    If the HISTTIMEFORMAT variable is set and not null, its value is used
    as a format string for strftime(3) to print the time stamp associated
    with each displayed history entry.  No time stamps are printed otherwise.

    Exit Status:
    Returns success unless an invalid option is given or an error occurs.

For more details, check the manual with man history

history - GNU History Library​

Examples​

To get help related to the history command use --help option​

`history` - GNU History Library

Examples

To get help related to the `history` command use `--help` option