Unlimited Bash History [closed]

After many large, ugly iterations and weird edge cases over the years, I now have a concise section of my .bashrc dedicated to this.

First, you must comment out or remove this section of your .bashrc (default for Ubuntu). If you don't, then certain environments (like running screen sessions) will still truncate your history:

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
# HISTSIZE=1000
# HISTFILESIZE=2000

Second, add this to the bottom of your .bashrc:

# Eternal bash history.
# ---------------------
# Undocumented feature which sets the size to "unlimited".
# http://stackoverflow.com/questions/9457233/unlimited-bash-history
export HISTFILESIZE=
export HISTSIZE=
export HISTTIMEFORMAT="[%F %T] "
# Change the file location because certain bash sessions truncate .bash_history file upon close.
# http://superuser.com/questions/575479/bash-history-truncated-to-500-lines-on-each-login
export HISTFILE=~/.bash_eternal_history
# Force prompt to write history after every command.
# http://superuser.com/questions/20900/bash-history-loss
PROMPT_COMMAND="history -a; $PROMPT_COMMAND"

Note: every command is written immediately after it's run, so if you accidentally paste a password you cannot just "kill -9 %%" to avoid the history write, you'll need to remove it manually.

Also note that each bash session will load the full history file in memory, but even if your history file grows to 10MB (which will take a long, long time) you won't notice much of an effect on your bash startup time.

• 3
  culprit at .bashrc, I had that setup after on another file loaded by .bashrc..., now working! thx!

  – Aquarius Power

  Jun 18, 2014 at 1:21
• 20
  Add it in my standard bash system, and adding current history is also nice, so after config, run cat ~/.bash_history >>~/.bash_eternal_history

  – Jean-Christophe Meillaud

  Aug 4, 2014 at 15:44
• 2
  To retain history history, initialize the history file with your current history.

  – Arthur

  Mar 26, 2015 at 23:10
• 3
  Bash truncates the history file during start up so you must comment out the default settings in .bashrc. Merely overriding the settings later in your own custom rc file will just leave you with the fruistrating situation where it looks like bash isn't respecting your changes to the history storage configuration.

  – studog

  Nov 17, 2017 at 15:14
• 9
  Many thanks - the fact that setting HISTFILESIZE (and possibly HISTSIZE) will take immediate effect cannot be overemphasized.

  – Attie

  May 21, 2018 at 11:18

Set HISTSIZE and HISTFILESIZE in .bashrc to an empty string:

HISTSIZE= 
HISTFILESIZE=

In bash 4.3 and later you can also use HISTSIZE=-1 HISTFILESIZE=-1:

n.  Setting HISTSIZE to a value less than zero causes the history list to be
    unlimited (setting it 0 zero disables the history list).

o.  Setting HISTFILESIZE to a value less than zero causes the history file size
    to be unlimited (setting it to 0 causes the history file to be truncated
    to zero size).

bash --version to check your bash version.

• 19
  (export PROMPT_COMMAND='history -a') can flush commands to bash history immediately.

  – cruelcage

  Sep 11, 2014 at 13:49
• 4
  Setting HISTSIZE= HISTFILESIZE= results in completely disabling the bash history, at least for me.

  – Philipp Ludwig

  Feb 27, 2017 at 7:53
• 7
  @PhilippLudwig setting HISTSIZE=-1 HISTFILESIZE=-1 disabled my history, while HISTSIZE= HISTFILESIZE= did the trick. CentOS 7 here.

  – Seether

  Jul 21, 2017 at 14:09
• 3
  @PhilippLudwig I think rather than HISTSIZE= HISTFILESIZE= you should export HISTSIZE= export HISTFILESIZE=

  – Matzz

  Feb 16, 2018 at 10:32
• 7
  @Seether The answer clearly states "In bash 4.3 and later...". CentOS 7 has bash 4.2.x.

  – villapx

  Feb 19, 2019 at 15:06

As Jörg Beyer mentioned in his answer, HISTSIZE and HISTFILESIZE are key.

In addition, you should definitely check out the environmental variable HISTCONTROL, which lets you do cool things like not store duplicate history commands (HISTCONTROL=erasedups). There's no point having unlimited history if you have to browse through hundreds of lines of cd .. or similar.

Links: here, and working with bash history. The bash Variable FAQ is also worth browsing.

• 21
  Those lines of cd give you context for the commands issued. They're actually incredibly useful. I can't understand why anyone would ever want to delete them, unless the only way you ever use history is by paging through it one command at a time.

  – iconoclast

  Jul 14, 2014 at 14:38
• @simont I also use the ignorespace option with HISTCONTROL then use this for anything I don't want written to history, such as passwords.

  – bigtunacan

  Nov 6, 2015 at 15:09
• 8
  Keeping the lines in order is very useful if you reuse sequences of commands. E.g. Ctrl-r somechars Ctrl-o Ctrl-o Ctrl-o Ctrl-o. That's why I keep duplicates in history.

  – Stéphane Gourichon

  Jan 5, 2016 at 18:53
• 2
  @StéphaneGourichon what's Ctrl-o for ?

  – Ciprian Tomoiagă

  Sep 26, 2018 at 8:22
• 10
  @CiprianTomoiagă Ctrl-o runs the command at prompt and shows right away the command right after the previous one in history. One benefit is that after using Ctrl-r to find an old command (possibly using up and down arrow to move to neighboring commands in history), it is enough to keep Ctrl pressed and press o multiple times to run again a previous series of commands, even in infinite loop if you want. See also GNU Readline - Wikipedia

  – Stéphane Gourichon

  Sep 26, 2018 at 11:12

There are (at least) two relevant env vars here:

• HISTSIZE: the number of entries that are stored in memory
• HISTFILESIZE: the number of lines tat are stored in history file

**details are here

I think that we can agree that the term unlimited is often the same as very big (or do you have unlimited file storage?). So just set the values very large.

• 31
  "It should be noted that 1000000000 is only equal to infinity for very small values of infinity. – sepp2k" lol. yes, i am content with small values of infinity (say, a month of frequent terminal use).

  – Francis Haart

  Feb 28, 2012 at 3:25
• 7
  a month of frequent terminal use is an infititesimally small fraction of infinity. I would say a lifetime of frequent terminal use equates to a very very very small value of infinity. But a lifetime of frequent terminal use is good enough for my shell history. ;)

  – iconoclast

  Jul 14, 2014 at 14:36
• 2
  Older versions of zsh at least will crash if you set HISTSIZE and/or HISTFILESIZE too large because it tries to pre-allocate enough memory. This became relevant when running tools that use zsh as their shell (dbx for example).

  – Brian Vandenberg

  Oct 9, 2017 at 19:09
• There are different types of infinity: see countably infinite and uncountably infinite. Inquiring minds might be interested.. and I'm fairly sure there are a lot of those hanging around stackoverflow.

  – demented hedgehog

  Dec 14, 2021 at 22:27