history

Display the full history list with line numbers.

history

Show only the most recent N entries.

history N

Re-run the command with the given history number.

!number

Re-run the previous command.

!!

Re-run the most recent command that starts with the given string.

!string

Press Ctrl+R to start a reverse incremental search (reverse-i-search). As you type, the most recent matching command appears. Press Ctrl+R again to step back through older matches. Press Enter to execute or Ctrl+G to cancel.

Ctrl+R

Display the most recent 10 history entries.

history 10
  491  grep "Kogami Shinya" crime_log.txt
  492  cat dominator_access.log
  493  wc -l case_archive.log
  494  ssh kogami@10.0.0.1
  495  cat sibyl_query.sh
  496  chmod +x sibyl_query.sh
  497  ./sibyl_query.sh
  498  ls -la /var/log/psycho_pass/
  499  diff crime_log.txt case_archive.log
  500  history 10

Re-run the command at history number 492.

!492
cat dominator_access.log
2040-04-01 09:12:33 Tsunemori Akane  LETHAL_ELIMINATOR granted
2040-04-01 09:18:47 Kogami Shinya    PARALYZER granted

Re-run the previous command with !!.

!!
cat dominator_access.log
2040-04-01 09:12:33 Tsunemori Akane  LETHAL_ELIMINATOR granted
2040-04-01 09:18:47 Kogami Shinya    PARALYZER granted

Re-run the most recent command starting with diff.

!diff
diff crime_log.txt case_archive.log

Delete history entry number 493.

history -d 493

Clear all in-memory history. Since it has not been written to file yet, the file is unaffected.

history -c
history

Write the current in-memory history to the file immediately (normally this happens only when the shell exits).

history -w

Add the following settings to ~/.bashrc to enable timestamped history.

~/.bashrc

export HISTTIMEFORMAT="%Y-%m-%d %T "
export HISTSIZE=10000
export HISTFILESIZE=20000
export HISTCONTROL=ignoreboth

The following example demonstrates this:

source ~/.bashrc
history 5
  496  2040-04-01 09:05:11  chmod +x sibyl_query.sh
  497  2040-04-01 09:06:03  ./sibyl_query.sh
  498  2040-04-01 09:10:44  ls -la /var/log/psycho_pass/
  499  2040-04-01 09:14:55  diff crime_log.txt case_archive.log
  500  2040-04-01 09:20:00  source ~/.bashrc

Configuration to share history across multiple terminals and append to the file on each exit.

~/.bashrc

# Append to history file instead of overwriting
shopt -s histappend

# After each command: write to file, clear memory, reload from file
PROMPT_COMMAND="history -a; history -c; history -r"

Bash history has a two-tier structure: in-memory history (the current session) and file-based history (~/.bash_history). By default, the file is written when the shell exits. Use history -w to write immediately and history -r to reload from the file.

Bang expansion (!) executes commands without confirmation. Before running !! or !string, you can preview the command using !!:p (print the previous command without executing) or !string:p to avoid surprises.

Setting HISTCONTROL=ignorespace prevents a command from being recorded by prefixing it with a space. This can be useful when handling sensitive information temporarily. However, see the common mistake below for an important caveat.

Common Mistake 1: History gets overwritten across multiple terminals

With Bash's default settings, when a shell exits, it overwrites ~/.bash_history with the current session's history. When multiple terminals are open simultaneously, only the history of the last terminal to close is preserved — commands run in other terminals are lost.

echo $HISTFILE
/home/kogami/.bash_history

Add the following to ~/.bashrc to make all terminals append to the shared history file instead of overwriting it.

~/.bashrc

# Append mode (default is overwrite)
shopt -s histappend

# After each command: write to file, clear memory, reload from all terminals
PROMPT_COMMAND="history -a; history -c; history -r"

history -a appends new entries from the current session to the file. history -c clears in-memory history. history -r reloads the file back into memory. Together, these three keep all open terminals in sync with the same up-to-date history.

Common Mistake 2: Passwords typed on the command line end up in history

Passing a password directly as a command argument stores it in ~/.bash_history in plain text. This creates a leak risk if another user shares the same machine or if the home directory is accidentally included in a backup.

mysql -u ginoza -pS1byl_P4ss database_sibyl

The command above is recorded in history exactly as typed. Several countermeasures are available.

Fix 1: Prefix the command with a space and enable HISTCONTROL=ignorespace.

~/.bashrc

export HISTCONTROL=ignoreboth

The following example demonstrates this:

 mysql -u ginoza -pS1byl_P4ss database_sibyl

The leading space (the very first character on the line) prevents this command from being recorded. However, this only works when HISTCONTROL is configured correctly — if the setting is missing, the command is still saved.

Fix 2: Do not put the password in the command arguments. Use a config file, environment variable, or interactive prompt instead.

mysql -u masaoka -p database_sibyl
Enter password:

Specifying -p without a value causes an interactive password prompt. The input is not recorded in history. This approach keeps the password out of history entirely.

Fix 3: If the password has already been recorded, delete it with history -d and flush the change to disk with history -w.

history | grep mysql
  342  mysql -u ginoza -pS1byl_P4ss database_sibyl
history -d 342
history -w