history

Overview

history shows the shell’s command history list (bash). Operators use it to recall prior commands, audit what was run in a session, and re-run lines with event designators (!!, !n). Configuration lives in HISTFILE, HISTSIZE, HISTFILESIZE, and related bash variables — deep customization belongs in shell-config docs.

Syntax

history [n]
history -c
history -d offset
history -a|-n|-r|-w [filename]

Without options, lists history with numbers.

Common Options

Option	Description
n	Show last n entries
-c	Clear history list
-d offset	Delete entry at offset
-a	Append new lines to $HISTFILE
-n	Read unseen lines from $HISTFILE
-r	Read file and replace current history
-w	Write current history to file
-p	Expand history designators (advanced)
-s	Append args as a single history entry

Examples with Explanations

Show recent commands

history | tail -20
history 30

Search history (interactive bash)

# Ctrl-R  reverse incremental search (readline)
history | grep ssh

Re-run by number / last command

!552          # re-run event 552
!!            # re-run last command
sudo !!       # common: repeat last with sudo

Be careful with destructive lines — review before firing !!.

Append now (multi-session)

history -a

Useful so another terminal can history -n and see your latest commands.

Clear session history

history -c
history -w    # optional: persist the empty/cleared state carefully

Clearing does not erase other users’ audits (journal, auth.log, bash_history on disk may still exist until overwritten).

Delete one awkward line

history | tail
history -d 1042

Still may exist in $HISTFILE until rewritten — know privacy limits of shell history.

Where history is stored

echo "$HISTFILE"          # typically ~/.bash_history
echo "$HISTSIZE" "$HISTFILESIZE"

Notes

• Commands prefixed with space may be omitted if HISTCONTROL=ignorespace (common).
• HISTCONTROL=ignoredups / erasedups change what gets stored.
• History is not a security log — rootkits and other shells won’t appear; privileged ops need proper auditing.
• zsh uses a different history system (fc, HISTFILE); this page is bash-oriented as Ubuntu default login shell for many admins.
• Avoid putting secrets on the command line; they land in history and process tables.

Related Commands

• type / command — resolve what will run
• alias — expansions that also show up as typed
• fc — fix/re-run history ranges (bash)
• script — full terminal typescript recording

Additional Resources

• help history
• man bash (HISTORY section)