Bash History – How to Set the Size of the History List in Bash to More Than 5000 Lines

bashlinuxshell

No matter how much I set the HISTSIZE environment variable to be larger than 5000, when printing the history list with the history builtin, it prints only the last 5000 commands.
I need that because I often have a large .bash_history which exceeds 5000 lines, and sometimes one needs to address an early command by pressing Ctrl-R, but if that command is more than 5000 commands earlier, I can't access it using that mechanism. I know I can use grep on the .bash_history, but I think the Ctrl-R mechanism would be much more faster (and convenient). I use gnu bash version 4.1.

That is the full content of my .bashrc file:

    #!/bin/bash
    # ~/.bashrc: executed by bash(1) for non-login shells.
    # see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
    # for examples

    # If not running interactively, don't do anything
    [ -z "$PS1" ] && return

    # don't put duplicate lines in the history. See bash(1) for more options
    # ... or force ignoredups and ignorespace
    #HISTCONTROL=ignoredups:ignorespace:erasedups

    # append to the history file, don't overwrite it
    shopt -s histappend

    # for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
    HISTSIZE=50000
    HISTFILESIZE=500000

    # check the window size after each command and, if necessary,
    # update the values of LINES and COLUMNS.
    shopt -s checkwinsize

    # make less more friendly for non-text input files, see lesspipe(1)
    [ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

    # set variable identifying the chroot you work in (used in the prompt below)
    if [ -z "$debian_chroot" ] && [ -r /etc/debian_chroot ]; then
        debian_chroot=$(cat /etc/debian_chroot)
    fi

    # set a fancy prompt (non-color, unless we know we "want" color)
    case "$TERM" in
        xterm-color) color_prompt=yes;;
    esac

    # uncomment for a colored prompt, if the terminal has the capability; turned
    # off by default to not distract the user: the focus in a terminal window
    # should be on the output of commands, not on the prompt
    #force_color_prompt=yes

    if [ -n "$force_color_prompt" ]; then
        if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
        # We have color support; assume it's compliant with Ecma-48
        # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
        # a case would tend to support setf rather than setaf.)
        color_prompt=yes

        else
        color_prompt=

        fi
    fi

    if [ "$color_prompt" = yes ]; then
        PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\         [\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
    else
        PS1='${debian_chroot:+($debian_chroot)}\@-\u@\h:\w\$ '
    fi
    unset color_prompt force_color_prompt

    # If this is an xterm set the title to user@host:dir
    case "$TERM" in
    xterm*|rxvt*)
        PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
        ;;
    *)
        ;;
    esac

    # enable color support of ls and also add handy aliases
    if [ -x /usr/bin/dircolors ]; then
        test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval    "$(dircolors -b)"
        alias ls='ls --color=auto'
        #alias dir='dir --color=auto'
        #alias vdir='vdir --color=auto'

        alias grep='grep --color=auto'
        alias fgrep='fgrep --color=auto'
        alias egrep='egrep --color=auto'
    fi

    # some more ls aliases
    alias ll='ls -alF'
    alias la='ls -A'
    alias l='ls -CF'

    # Alias definitions.
    # You may want to put all your additions into a separate file like
    # ~/.bash_aliases, instead of adding them here directly.
    # See /usr/share/doc/bash-doc/examples in the bash-doc package.

    if [ -f ~/.bash_aliases ]; then
        . ~/.bash_aliases
    fi

    # enable programmable completion features (you don't need to enable
    # this, if it's already enabled in /etc/bash.bashrc and /etc/profile
    # sources /etc/bash.bashrc).
    if [ -f /etc/bash_completion ] && ! shopt -oq posix; then
        . /etc/bash_completion
    fi

Best Answer

This is the actual code that loads the history (from bashhist.c around line 260):

/* Load the history list from the history file. */
void

load_history ()
{
  char *hf;

  /* Truncate history file for interactive shells which desire it.
     Note that the history file is automatically truncated to the
     size of HISTSIZE if the user does not explicitly set the size
     differently. */
  set_if_not ("HISTSIZE", "500");
  sv_histsize ("HISTSIZE");

  set_if_not ("HISTFILESIZE", get_string_value ("HISTSIZE"));
  sv_histsize ("HISTFILESIZE");

  /* Read the history in HISTFILE into the history list. */
  hf = get_string_value ("HISTFILE");

  if (hf && *hf && file_exists (hf))
    {
      read_history (hf);
      using_history ();
      history_lines_in_file = where_history ();
    }
}

If the values of HISTSIZE and HISTFILESIZE are set, they will be used.

Readline, the library that actually handles input / line editing and history does offer facilities to put a cap on just how big the history buffer can grow. However, Bash does not place a hard ceiling on this where values any larger would be ignored, at least that I could find.

Edit

From comments, readline was indeed the culprit. I was looking (rather foolishly) at functional parameters:

there is a variable called history-size that can be read from the inputrc file. that variable sets the maximum number of history entries saved in the history list. I checked it's value in my local inputrc file to found it equal 5000. Setting it to a larger value solved the problem.

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