Prevent duplicates from being saved in bash history

JPLemme_1019 0
Viewed 24997

I'm trying to prevent bash from saving duplicate commands to my history. Here's what I've got:

shopt -s histappend
export HISTIGNORE='&:ls:cd ~:cd ..:[bf]g:exit:h:history'
export HISTCONTROL=erasedups
export PROMPT_COMMAND='history -a'

This works fine while I'm logged in and .bash_history is in memory. For example:

$ history
    1 vi .bashrc
    2 vi .alias
    3 cd /cygdrive
    4 cd ~jplemme
    5 vi .bashrc
    6 vi .alias

$ vi .bashrc

$ history
    1 vi .alias
    2 cd /cygdrive
    3 cd ~jplemme
    4 vi .alias
    5 vi .bashrc

$ vi .alias

$ history
    1 cd /cygdrive
    2 cd ~jplemme
    3 vi .bashrc
    4 vi .alias

$ exit

But when I log back in, my history file looks like this:

$ history
    1 vi .bashrc
    2 vi .alias
    3 cd /cygdrive
    4 cd ~jplemme
    5 vi .bashrc
    6 vi .alias
    7 vi .bashrc
    8 vi .alias

What am I doing wrong?

EDIT: Removing the shopt and PROMPT_COMMAND lines from .bashrc does not fix the problem.

cygwin command-line history bash
5 Answers

The problem is definitely the histappend. Tested and confirmed on my system.

My relevant environment is:

$ set | grep HIST
HISTFILE=/Users/hop/.bash_history
HISTFILESIZE=500
HISTIGNORE=' *:&:?:??'
HISTSIZE=500
$ export HISTCONTROL=erasedups
$ shopt | grep hist
cmdhist         on
histappend      off
histreedit      off
histverify      off
lithist         off

Now that I think about it, the problem is probably with the history -a. history -w should write the current history without any duplicates, so use that if you don't mind the concurrency issues.

Admin1 
export HISTCONTROL=ignoreboth
Robert_Gamble_252220

Here is what I use..

[vanuganti@ ~]$ grep HIST .alias*
.alias:HISTCONTROL="erasedups"
.alias:HISTSIZE=20000
.alias:HISTIGNORE=ls:ll:"ls -altr":"ls -alt":la:l:pwd:exit:mc:su:df:clear:ps:h:history:"ls -al"
.alias:export HISTCONTROL HISTSIZE HISTIGNORE
[vanuganti@ ~]$

and working

[vanuganti@ ~]$ pwd
/Users/XXX
[vanuganti@ ~]$ pwd
/Users/XXX
[vanuganti@ ~]$ history | grep pwd | wc -l
       1
user_5676790

inside your .bash_profile add

alias hist="history -a && hist.py"

then put this on your path as hist.py and make it executable

#!/usr/bin/env python

from __future__ import print_function
import os, sys
home = os.getenv("HOME")
if not home :
    sys.exit(1)
lines = open(os.path.join(home, ".bash_history")).readlines()
history = []
for s in lines[:: -1] :
    s = s.rstrip()
    if s not in history :
        history.append(s)
print('\n'.join(history[:: -1]))

now when you want the short list just type hist

user_5145700
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